Design report: Piled foundations

Final Design Report

Piled Foundations

DESIGN REPORT: PILE FOUNDATIONS.

TABLE OF CONTENTS

21Overall soil conditions.

2Soil parameters23Pile Capacities53.1Empirical method for granular soils5a.Bored piles.63.2Static method for granular soils7a.End bearing7b.Shaft resistance93.3Static method for cohesive soils93.4Adopted design parameters104Foundation Conditions124.1NH1 Interchange124.2Nuoc Len Bridge124.3Rach Cay Bridge134.4Lo Gom Bridge134.5Cha Va Bridge144.6Calmette Bridge144.7Khanh Hoi Bridge144.8Ca Tre Lon Bridge154.9Ca Tre Nho Bridge154.10Hanoi Highway Flyover154.11Footbridges165References:19

TABLES

11Table 1 -Pile Capacity Calculation Sheet

Table 2 -Major Bridges: estimated pile tip elevations17Table 3 -Footbridges: estimated pile tip elevations18

FIGURES

2Figure 1 -Profile of soft organic clays along the project road

Figure 2 -SPT versus Unit Weight3Figure 3 -SPT versus undrained strength3Figure 4 -SPT depth correction factor, CN4Figure 5 -Friction angle versus N605Figure 6 -Shaft friction factor for driven and bored piles6Figure 7 -Bearing capacity factor Nq from various sources8Figure 8 -Tomlinsons adhesion factor for piles in cohesive strata9

APPENDICES

1. Comparison of pile design methods for granular soils

2. Major Bridges Pile Capacities

3. Footbridges Pile Capacities

DRAWINGS

01 10 Plan and Soils Profiles of Major Bridges

1 Overall soil conditions.

Beneath a thin surface layer of topsoil or fill, the uppermost natural soil layer, which was found across almost the entire length of the road, was a very soft to soft, organic clay of medium to high plasticity. The thickness of this layer, which is shown on Figure 1, was found to vary from 25 to 40 m between km 0 and km 5.5 and then to change suddenly to less than 5 m along the bank of the Ben Nghe Canal up to km 14. On the Thu Thiem side, the thickness of the organic clay was generally found to range between 10 and 20 m except between km 18.7 and 20.5 where it was generally less than 5 metres.

Figure 1 - Profile of soft organic clays along the project road

Beneath the soft organic clay, medium dense sandy soils were mostly encountered down to elevation 30 to 40 m, where very stiff to hard clays were found to extend 15 to 20 m. The clay was found in turn to overlie dense to very dense sands.

2 Soil parameters

The soft organic clay was found to have SPT N values of 0 to 3 blows/ft, and corresponding undrained shear strengths typically about 10 to 20 kPa, reaching 30 to 40 kPa near the bottom of the layer. Moisture contents were generally over 100 per cent in the upper part of the layer, well above the liquid limit. Organic contents were found to be about 10 per cent.

The underlying medium dense sand layers had N values ranging from 12 to 30 blows/ft. This is not a competent layer for the founding of piles. The very stiff to hard clay layer has generally high SPT resistances of 30 to 50, corresponding to undrained shear strengths of 180 to 300 kPa. However, it is not until the underlying sand layers are reached that a satisfactory end bearing capacity can be mobilised for driven or bored piles.

The unit weight of the various soil layers depends predominantly on their natural moisture contents, and thus their densities. In the pile calculations, the effective overburden pressure has been calculated assuming the relationship between the unit weight and N value given in Figure 2 below. The plotted points in the Figure represent the approximate ranges of unit weight suggested by Meyerhof for different relative densities.

Figure 2 - SPT versus Unit Weight

Shear strengths of cohesive and granular soils have been correlated with SPT values by Terzaghi & Peck and later modified by Meyerhof (1). Various undrained shear strength relationships are shown in Figure 3, the upper being the Terzaghi & Peck relationship and the lower being that suggested in the British Code, CP2004, 1972. The centre line has been drawn as a best fit of the vane test results carried out for the project and the upper boundary of the unconfined compression tests carried out for this project, the Binh Thuan Raod and the Maunsell tunnel borings (2). The equation of this line is Su = 20 + 5.N, where Su is measured in kPa. It should be noted that this line does not pass through the origin. This is consistent with field results: the split spoon sampler may sink the full 45 cm under the weight of the rods and hammer giving a zero N value, even though the clay have a shear strength of 20 kPa. This line has been used in the pile capacity calculations.

Figure 3 - SPT versus undrained strength

The unconfined tests all lie below the design line, and this is attributed to the normal degree of sample disturbance which is to be expected. The vane tests results may be taken as the true measure of undrained shear strength, and these points are both above and below the line.

In developing a relationship between the angle of friction of a cohesionless soil and the measured SPT resistances, it was found that the N values should be corrected for overburden pressure which gives an additional apparent resistance in deep borings which is not attributable to shear strength. The SPT correction for both hammer efficiency and depth is given in the US Corps of Engineers Manual, EM 1110-1 (3) as follows:

N60 = CER..NSPT

equ. 1

where CER is the hammer energy correction factor (= 1 for a free fall hammer),

CN is the depth correction factor.

Figure 4 - SPT depth correction factor, CNThe relationship between CN and effective overburden pressure is given in the COE Manual on the basis of data from Tokimatsu and Seed (4) as shown in Figure 4 and this was used in the spread sheets to calculate N60 .

The relationship between N60 and friction angle, , is taken from the range of values proposed by Meyerhof as given in Table 3-1 of the COE Manual. These values are plotted below in Figure 5, and were found to give a good straight line fit when is plotted against log10 N. This line is defined by

= 4.1057.loge(N60) + 24.707

equ. 2

This relationship has been used in the spreadsheets to calculate the bearing capacity of piles in granular strata.

The correlation between and SPT blow counts is difficult to verify since only disturbed samples can be taken from the granular soil strata and triaxial tests can only be made on recompacted samples. Although the use of SPT resistances to predict friction angles and relative densities is only approximate, it still provides a rational method of estimating pile capacities. However, such estimates must be confirmed by full scale load testing during construction.

Figure 5 - Friction angle versus N603 Pile Capacities

3.1 Empirical method for granular soils

a.Driven piles

Since it is difficult to measure the in-situ shear strength parameters of granular strata, an empirical relationship was proposed by Meyerhof in 1976 (5) between the capacity of driven piles and SPT resistance. This relationship, which is valid only for cohesionless soils, has become widely accepted as giving a reasonable estimate of pile bearing capacity: it is quoted in Leonards, Foundation Engineering, (6), the COE Manual EM 1110-1, the Navys Design Manual 7.02 (7), and Hsai-Yang Fangs Foundation Engineering Handbook (8).

For driven piles, the ultimate bearing capacity is given by:

Total ultimate capacity

Qult = Qt + Qs

kN

equ. 3

End bearing capacity

Qt = At.m.Nt

kN

equ. 3.1

Shaft friction capacity

Qs = As.Lp.fs

kN

equ. 3.2

Shaft resistance

fs = n.Nave

kPa

equ. 3.3

Allowable capacity

Qall = (Qs + Qp)/FkN

equ. 3.4

where

m, n are empirical coefficients,

At is the cross-sectional area of the pile at the tip (m2),

As is the surface area of the pile per unit length (m2),

Lp is the embedded length of the pile in bearing strata (m),

Nave is the average corrected SPT resistance over the length of the pile,

Nt is the SPT resistance at the pile tip.

F is the factor of safety, here set at 3.0.

It should be noted that the coefficients m and n are not dimensionless but have the dimensions of force per unit area. Various references, compared in Appendix 1, give bearing resistances in tons/ft2, some in kips/ft2 and some in kPa. In the following text, the values of m and n are in kPa.

There is a consensus among the references named above on the values of m and n for driven piles. Expressed in SI units, for driven piles, m = 400 and n = 2. The end bearing capacity calculated by the above equation was found to agree quite well with the capacities derived from the static formulae described below. However, the shaft resistances for driven piles in medium dense soils were somewhat lower than those calculated from the static formulae. In such cases, a better agreement was found by using n = 3 since the empirical formula tends to underestimate the friction angle of looser soils. In denser soils, there was good agreement between the static and empirical formulae using n = 2, and this value was therefore adopted in the calculations.

In silty sands or very fine sands, Leonards recommends that the corrected SPT resistance, N, should be used to estimate pile capacity. This is also corroborated by the Navy Manual, which recommends that m = 300 be used for silts. N is given by the formula:

N = 15 + (N 15)/2 for N > 15

equ. 4

where

N is the measured SPT driving resistance in blows/foot.

In applying the above equations, only dense granular soil strata should be considered. Where soft soil strata overlie dense strata, the soft layers do not contribute to the piles capacity, and in some cases detract from it due to negative skin friction from consolidation of the soft layers. Shaft resistance in these soft strata is therefore ignored.

In cohesive strata, the empirical formulae are not valid and pile capacities are calculated based on the measured or derived undrained shear strengths as described in Section 3.3 below.

a. Bored piles.

With bored piles, no displacement or densification of soil occurs during installation and lower values of the coefficients m and n are to be expected. For end bearing, Fang recommends m = 120, ie. 30 per cent of the value for driven piles; the Navy Manual states that the bearing resistance is 1/3 of the value for driven piles, ie. m = 128 in SI units. For shaft resistance, Fang recommends n = 1, ie. 50 per cent of the value for driven piles, and this is also recommended by the US Navy. The Corps of Engineers does not give empirical formulae for bored piles.

Figure 6 - Shaft friction factor for driven and bored piles

While the empirical coefficients for end bearing give results which are comparable with the static formulae, correspondence is not so good with the shaft resistance. As shown in Figure 6, COE found that shaft resistances for bored piles were about one third of those for driven piles. On the basis of these considerations, the following m and n coefficients have been adopted:

Driven piles: m = 400, n = 2

Bored piles:m = 133, n = 0.67

3.2 Static method for granular soils

a. End bearing

The end bearing capacity of a pile is given by the Terzaghi equation:

Qt = At ( c.Nc + ..B.N + .d.Nq)

equ. 5

where Nc, Ng, Nq are the dimensionless bearing capacity factors depending on the angle of friction ,

c is the effective cohesion of the soil,

is the unit weight of the soil,

d is the depth of the pile tip.

For cohesionless soils, c = 0 and, for deep foundations, ..B.N is small compared with .d.Nq. The above equation may therefore be simplified to:

Qt = At.qt

equ. 5.1

where qt = pt.Nq

equ. 5.2

and pt is the effective overburden pressure at the pile tip.

The value of Nq, which is dependent on friction angle alone, has been studied by many researchers giving a wide variety of results. Some of these, which have been quoted above, are shown in Figure 7.

The Terzaghi and Peck line, D, which was developed for shallow strip footings, was found to give very conservative estimates of end bearing capacity for driven piles, but was found by Fang and Caltrans (9) to give reasonable estimates for bored piles. This line has therefore been used for bored piles.

The COE Manual 1110-2 (10) recommends that end bearing capacities for driven piles be based on values between curves B and C. Fang also gives tip bearing coefficients between these curves, shown on the figure as single points. Curve B gives capacities about 1/3 higher than C, and the latter more conservative values have therefore been adopted for calculating driven pile end bearing capacities.

In applying equation 5.1, many researchers have found that, although qt is directly dependent on pt up to certain depths, there appears to be a limiting depth below which there is no increase in bearing resistance. The COE Manual EM 1110-2 defines this critical depth beyond which the end bearing capacity is constant as 10xB for loose sands, 15xB for medium dense sands and 20xB for dense sands, where B is the width of the pile. The COE Manuals are not completely clear on where this depth should be measured from if the bearing strata are overlaid by a thick soft clay stratum. In the Navy manual, it is clearly stated that the critical depth should be taken as 20xB below the bearing stratum.

Fang is rather sceptical about the critical depth concept, both when applied to end bearing and also when applied to shaft resistance. Referring to shaft friction, he writes It has been suggested that the above effective stress relationship ceases to be valid at a certain critical depth equal to 10 to 20 pile diameters. Below the critical depth, the unit shaft resistance would be constant and equal to the value at the critical depth. However, the concept of critical depth is unproven and in question. It should therefore be applied with caution, if atall.

For the present calculations, the US Navy guidelines have been followed, with the critical depth being measured from the bottom of the soft upper clay layers.

In COE Manual 1110-1, the Meyerhof method gives an upper limit for bearing capacity, independent of depth and overburden pressure in the following equation:

QL = 48.At.Nqp.tan'

equ. 6

whereNqp is a limiting bearing capacity factor taken from Curve A.

This equation was found to give end bearing values of about half of those given by Equation 5.1 and considerably below the values given by the empirical method.

Figure 7 - Bearing capacity factor Nq from various sources

Limiting values of ultimate end bearing resistance are given in various sources. Caltrans gives a maximum qt value of 90 ksf (4,300 kPa) for bored piles and Tomlinson suggests a maximum of 11,000 kPa.

b. Shaft resistance

The static formula for shaft resistance is:

Qs = L.As.po'.K.tan

equ. 7

where L is the length of a pile segment

As is the unit area of the pile circumference,

po' is the effective overburden pressure at the mid point of the pile segment,

K is the earth pressure coefficient, and

is the friction angle between the soil and the pile.

Driving displacement piles causes an increase in the lateral earth pressure due to displacement of the soil and densification in medium of loose sands. The actual value of K depends both on the friction angle and the overconsolidation ration of the stratum. A wide range of factors are quoted for K, from 0.5 for loose sands to between 1.0 and 2.0 for dense sands. In the calculations for driven piles, a value 0.8 has been selected. For bored piles, where there is no densification from the pile installation, 1/3 of this value has been selected. This is in accordance with the curves for driven and bored piles shown in Figure 6.

3.3 Static method for cohesive soils

The empirical equations, 3.1 to 3.3, are not valid for cohesive soils and the static method based on undrained shear strengths must be used in stead. The undrained shear strength, Su, of a cohesive layer is derived from the relationship between Su and SPT N shown in Figure 3. The bearing capacity equations for piles in cohesive strata are not dependent on overburden pressure so that the critical depth factor does not apply. The end bearing capacity may then be calculated using the following equation:

Qt = At.Su.Nc

equ. 8

whereSu is the undrained shear strength,

Nc is a bearing capacity factor depending on depth. For D/B > 4, Nc = 9.

Figure 8 - Tomlinsons adhesion factor for piles in cohesive strata

Shaft resistance is given by the following equation:

Qs = (L.As.Su.Fa)

equ. 9

whereFa is the adhesion factor given in Figure 8.

The adhesion between the pile and the clay depends solely on the undrained shear strength of the clay. For soft clays, the adhesion is equal to the undrained shear strength, but for stiffer clays, the adhesion becomes progressively less than the shear strength. Tomlinsons (11) relationship between adhesion and undrained shear strength, here shown in Figure 8 for concrete or timber piles, is widely accepted and has been adopted in the calculations.

For bored piles, COE and Caltrans give a limiting value of 80 ksf (3,840 kPa) for end bearing resistance and 5.5 ksf (264 kPa) for shaft friction, with special attention being paid to the effects of bentonite on the adhesion factor.

3.4 Adopted design parameters

A comparison of the various methods of calculating pile capacities, which have been described in the previous sections, is given in Appendix 1. This appendix also gives the parameters adopted in the calculations.

An example of the pile capacity calculation sheet is shown in Table 1. Where very soft soils are encountered, no capacity is transferred to the pile. Where cohesive soils are encountered, C is entered in the soil strata column and the undrained shear strength is used to calculate tip and shaft resistances as described in Section 3.3. Where granular strata are encountered, G is entered in the soil strata column and both the empirical and static methods are used to calculate pile capacity as described in Sections 3.1 and 3.2. Different Nq and shaft resistance factors are used for driven and bored piles.

The parameters may be summarised as follows:

Soil typeDriven pilesBored piles

Cohesive strataNc = 9

Fa from Fig. 8

Granular strataEmpirical methodm = 400

n = 2m = 133

n = 0.67

Static MethodNq from Fig. 7, Curve C

K = 1.0, = 0.8Nqp from Fig. 7, Curve A

K = 0.33, = 0.8

In view of the considerable differences in bearing capacities that can be obtained using the various methods described above, especially in the choice of Nq, some careful judgement is needed in determining the design values.

In granular strata, the basis of the static method is the effective friction angle, which is inferred from the SPT resistances. This relationship is only approximate and, in any case, the in-situ strength properties of granular soils are very dependent on the type and installation method of the piles (ie. driven or bored). Both the empirical method and the static method are thus dependent on empirical relationships based on SPT values. Equal weight has therefore been placed on the results derived by both methods and the required tip levels for driven piles have therefore been set by taking the average of the total capacity lines derived by both methods.

For bored piles, the required tip elevation has been set according to shaft resistance. Again, an average has been taken of the values derived by the static and empirical methods.

Table 1 - Pile Capacity Calculation Sheet

4 Foundation Conditions

There are 13 major bridges and 10 footbridges for which subsoil investigations were carried out. The soil conditions at each bridge site has been assessed and pile capacities have been estimated in accordance with the design procedures described in the previous section. The results of the pile bearing capacity calculations for each bridge have been given in Appendices 2 and 3 and the required tip elevations are summarised in Tables 2 and 3 at the end of this section.

For driven piles, the required tip elevations are determined from the total pile capacity, end bearing plus shaft resistance. For 350 and 450 mm square piles, target ultimate capacities of 2,000 and 3,000 kN have been set. For bored piles having larger diameters of 750, 1000 and 1500 mm, end bearing is only mobilised at quite large settlements compared with shaft resistance. The required pile tip elevations have accordingly been set where the shaft resistance on its own reaches the working load, here taken as 2,000 for the 750 mm diameter piles, 3,000 kN for 1000 mm diameter piles and 5,000 kN for 1500 mm diameter piles.

The following paragraphs give brief descriptions of the soil conditions at each bridge site with reference being made to the Reports on Soil Investigation prepared by the Consultants (12) under separate cover.

4.1 NH1 Interchange

The site of the interchange, shown on Drawing 01, is heavily built up on the north west side of the existing road, but is open paddy land on the opposite side. Four borings were made at the interchange site: five had originally been scheduled, but access was denied to the drilling team to carry out HI2. HI1 had to be moved about 40 m away from its planned location due to access difficulties.

Beneath 0 to 2 m of fill, the borings encountered soft organic clay down to 20 to 22 m depth. SPT resistances of 1 to 4 blows/foot were recorded with corresponding vane strengths of 17 to 48 kPa.

Beneath the soft upper clay stratum, medium to dense sands, clayey sands and sandy clays were encountered to the end of the borings, at 40 to 60 metres depth. SPT resistances were generally between 25 and 30 blows/foot, with a few layers giving up to 40 blows. A 2 m clayey layer was encountered at 39 m depth in Boring HI3 where blow counts dropped to 15: a similar drop in blow count was recorded in Boring HI4 at about the same depth. In Boring HI5, gravelly sand was encountered below 50 m depth having SPT blow counts of 28 to 31.

The results of the pile capacity calculations are shown in Appendix 2.1. For driven 450 mm piles, the required bearing of 3,000 kN is reached at about elevation 26 m, except at boring HI5, where piles should be taken down below the sandy clay layer at 38 m. The required bearing is reached at 40 m.

Bored piles need to be taken down much further than the driven piles since the required shaft resistance is not reached until tip levels of - 53 to 60 m have been reached. The same tip levels were estimated for both sixes of bored pile.

Negative friction on the piles has been estimated due to settlements in the very soft clay under embankment loads, such as may be expected at abutment approach ramps. For the 450 mm driven piles, up to 1,160 kN may be expected, and up to 2,000 and 3,000 kN for the 1000 mm and 1500 mm bored piles respectively.

4.2 Nuoc Len Bridge

Similar subsoil conditions to those described above were encountered at the Nuoc Len Bridge. The bridge site, shown on Drawing 02, is low lying ground most excavated as fish ponds. Here, six borings were made to between 30 and 60 m depth. The upper very soft organic clay was encountered from ground level to depths of 22 to 25 m. SPT blow counts varied between 1 and 4 blows/foot and vane shear strengths varied between 19 and 52 kPa. A layer of firm plastic clay, 1.5 to 7 m thick, was encountered under the soft clay in the three borings at the west end of the site having SPT resistances of 5 to 7 blows/foot.

Beneath the upper clay layers, medium to dense sands were encountered in all the borings to the depths drilled. SPT resistances were generally fairly constant at 30 to 40 blows/foot, although in Borings NL3 and NL4, looser sands were found down to about 45 m depth. In two of the borings, a 1m stiff sandy clay layer was encountered at 37 to 41 m depth. Gravelly sand found at 53 m depth in Boring NL4.

The required tip elevations, shown in Appendix 2.2, are similar to those for the NH1 interchange. Driven 450 mm piles will reach their required bearing of 3,000 kN at about elevation - 30 to - 40 m. The deeper levels are required under the centre of the channel, Borings NL3, NL4 and NL5, where the upper part of the sand layer is less dense than at the other borings. Tip elevations for bored piles are estimated to vary between 50 to 63 m, the lower levels also being estimated for Boring NL4.

As at the NH1 interchange, negative friction forces are also expected to be significant. These have been estimated up to 1,100, 1,980 and 2,970 kN for the 450 mm driven and 1000 mm and 1500 mm bored piles respectively.

4.3 Rach Cay Bridge

Two borings were made at the Rach Cay Bridge site as shown on Drawing 03. The very soft organic clay was found to be 20 to 23 m thick, and to have vane shear strengths of 19 to 43 kPa. Three SPTs gave blow counts of 1 blow/foot. Beneath the clay, loose clayey sand was encounterd down to 35 m depth with SPT resistances of 3 to 7 blows/foot. Below the clayey sand, an 8 m layer of dense medium fine sand was encountered in both borings. In Boring RC1, this was in turn underlain by a 9 m thick layer of very stiff clay (N = 24 to 38) and dense medium fine sand (N = 27 to 31) down to the end of the boring at 60 m.

The required pile tip elevations for the driven 450 mm piles depend in this case on the depth of the very stiff clay layer. The overlying dense sand is not considered sufficiently thick to develop the required full ultimate capacity so that piles will need to be taken down into the very stiff clay. The required ultimate capacity of 3,000 kN will probably be achieved in the middle of this layer, ie. at about 50 m. The bored piles will need to be taken deeper to mobilise the required shaft resistance. They will therefore be founded in the underlying dense sand at elevations 57 and 59 m for the 1000 and 1500 mm diameter piles respectively. These estimated tip elevations are given in Appendix 2.3.

Negative friction forces have been estimated up to 875 kN for the 450 mm driven piles and up to 1,500 and 2,300 kN for the 1000 and 1500 mm bored piles.

4.4 Lo Gom Bridge

The Lo Gom Bridge has the most critical foundation conditions of any of the bridge sites. Six borings were made to depths of 55 to 70 m, as shown on Drawing 04. The very soft organic clay was found to extend down to depths of between 39 and 42 m below ground: SPT resistances varied between 1 and 4 blows/foot, and vane shear strengths varied from 16 to 43 kPa.

Beneath the very soft clay, a 1.5 to 6 m thick layer of medium to dense sand was found in which SPT values of about 20 blows/foot were recorded. Below the sand, a 7 to 13 m layer of very stiff clay to sandy clay was encountered in all the borings in which SPT resistances of 25 to over 50 blows were recorded. Below the clay, dense sand was again encountered to the depths bored.

The foundation conditions are quite uniform across the bridge site. Piles will need to be taken down to the dense sand layer beneath the very stiff clay to achieve sufficient bearing capacity. The estimated required tip elevations, given in Appendix 2.4, were between 52 and 56 m for driven piles, and 54 and 64 m for bored piles.

Due to the 40 m thick layer of soft organic clay, high negative friction loads are likely to be caused by consolidation settlements beneath the approach embankments. These are estimated to be up to 2,200 kN for 450 mm driven piles and up to 3,800 and 5,700 kN for 1000 and 1500 mm diameter bored piles.

4.5 Cha Va Bridge

The foundation conditions at the Cha Va Bridge site are much better than at the previous bridges, see Drawing 05. 1.5 to 3 m of fill was found in the land borings, CV 4, CV2 and CV7, below which the soft organic clay layer was only found to be 1.5 to 3 m thick and was not found at all in Boring CV4. Within the next 10 m, firm sandy clays and clayey sands were found with SPT resistances of 9 to 16 blows/foot. Beneath this, medium dense sands were encountered down to depths of 35 to 40 m with SPT blow counts typically ranging from 10 to 20 blows/foot.

Beneath the medium dense sand stratum extending down to elevation 48 to 49 m, very stiff clay was found in all the borings interspersed with a layer of stiff sandy clay. Beneath the clay, dense sand was encountered to the depths bored.

The pile capacity calculations, given in Appendix 2.5, show that both driven and bored piles need to be taken down to the very stiff clay layer to reach the required bearing capacities. The required tip elevations for 450 mm driven piles were estimated to be between 41 and 49 m, while for bored piles, they were estimated between 38 and 45 m.

Negative friction loads are not expected at this site, since the very soft clay stratum is less than 3 m thick and this will be excavated during construction of the abutments.

4.6 Calmette Bridge

Seven borings were made at the Calmette Bridge site, shown on Drawing 06: five on the main line of the bridge and two additional beneath the lateral approach ramps on the south side of the Ben Nghe Canal. Beneath 1 to 2 m of fill, very soft organic clay was encountered down to depths of between 5 and 10 m. Beneath this, medium dense sands interbedded with firm sandy clays and medium dense clayey sands were found to extend down to elevation 38 m, where very stiff clay was encountered in all the borings. The stiff clay layer extended down to 52 to 53 m, beneath which dense to very dense sand was found.

To obtain the required bearing capacities, both driven and bored piles will need to be taken down to the very stiff clay layer below 38 m, although driven piles near Boring CF2 may refuse in the dense sand just above this layer. Estimated tip elevations, given in Appendix 2.6, vary between 33 and 50 m for the driven 450 mm piles and 41 to 48 for the 1000 and 1500 mm diameter bored piles.

Negative friction loads due to consolidation beneath abutment fill could reach 350 kN for the 450 mm driven piles and 600 and 920 kN for the 1000 and 1500 mm bored piles respectively.

4.7 Khanh Hoi Bridge

Five borings were made at the Khanh Hoi Bridge site as shown on Drawing 07. 2 to 4 m of fill was encountered in the land borings: beneath this and from the canal bed in Boring KH3, very soft to soft organic clay was found to extend down to between 5 and 9 m depth. SPT resistances varied between 1 and 3 blows/foot and vane shear strengths of 18 to 55 kPa were recorded. Beneath the soft clay, a very dense lateritic gravel or gravelly sand layer 4 to 6 m thick was encountered in Borings KH1 and KH2. Beneath this, and below the soft clay in the other borings, medium dense silty and clayey sands and firm sandy clays were encountered down to elevation 20 to 23 m. Below this level, clean medium dense sands were found to extend down to a layer of very stiff to hard clay encountered at 29 to 33 m. This stratum was found to be 17 m thick in Boring KH3, below which very dense gravelly sand was found.

The founding stratum in all the borings is the very stiff clay in which SPT resistances ranged from 27 to over 50 blows/foot. To reach the set pile capacities, tip levels of 34 to 39 were estimated for the driven 450 mm piles, and 34 to 41 for the bored piles, as shown in Appendix 2.7. Potential negative friction loads of 460 kN are estimated for the driven 450 mm piles and 800 and 1200 kN for the 1000 and 1500 mm bored piles respectively.

4.8 Ca Tre Lon Bridge

Five borings were made at the Tre Lon Bridge site to depths of 50 to 65 m as shown on Drawing 08. The site is in low-lying swampy ground with very soft organic clay encountered from the ground surface to about 15 m depth. Vane shear strengths were measured at both abutment borings and showed the strength to increase from 15 to 20 kPa near ground level to 30 to 35 kPa at the base of the layer. Below the very soft clay, a 5 to 6 m thick layer of stiff to very stiff clay was encountered in all the borings with SPT resistances of 12 to 18 blows/foot.

Beneath the stiff clay, medium dense clean sands, silty and clayey sands and sandy clays were found interbedded in all the borings. SPT resistances were typically between 15 and 25 blows/foot. In Borings TL1 and TL4, these sandy layers were underlain at about 52 m depth by a thin firm to stiff clay layer with SPT blow counts dropping to as low as 9 blows/foot. Below this, dense sand was encountered in both borings where SPT resistances were between 35 and 41 blows/foot .

The required pile tip elevations given in Appendix 2.8 were estimated at 31 to 33 m for the driven 450 mm piles. For the bored piles, required tip elevations varied from 48 to 54 m, with tip levels for the 1500 mm diameter piles being about 1 m lower than for the 1000 mm piles.

Potential negative friction loads are likely to be quite significant. They were estimated at up to 580 kN for the 450 mm driven piles and 1,000 to 1,500 kN for the 1000 and 1500 mm bored piles.

4.9 Ca Tre Nho Bridge

Very similar conditions to the above were found at the Ca Tre Nho Bridge site where five borings were made to depths of 50 to 67 m as shown on Drawing 09. Here the soft organic clay was encountered to depths of 15 to 24 m, with vane shear strengths between 13 and 42 kPa. SPT resistances varied between 0 and 5 blows/foot. Beneath the organic clay, stiff clays and sandy clays were encountered down to depths of 25 to 30 m with SPT blow counts of 7 to 18. Beneath this, a 7 to 10 m thick layer of very stiff to hard clay was found to overlie interbedded layers of sandy clays, clayey to silty sands and clean sands. These layers were medium dense to dense with SPT blow counts ranging between 10 and 40.

Pile tip elevations have been estimated as shown in Appendix 2.9. All piles need to be taken down through the very stiff clay layer to the medium dense to dense sandy stratum encountered below -37m. For the 450 mm driven piles, required tip elevations were found to vary from 39 m at the west abutment to 48 m at the east abutment. For the bored piles, slightly shallower tip elevations were estimated: 35 and 37 m for the 1000 and 1500 mm piles at the west abutment to 44 and 47 m for the two pile sizes at the east abutment.

Potential negative friction loadings on driven 450 mm piles also varied from 650 to 1,270 kN at the west to east abutments respectively. Corresponding loads for the two bored pile sizes were estimated at 1,125 and 1,687 kN at the west abutment and 2,217 and 3,326 kN at the east abutment.

4.10 Hanoi Highway Flyover

Four borings were made to depths of 50 to 60 m at the site of the Hanoi Highway Flyover as shown on Drawing 10. Beneath a fill layer 1 to 2 m thick, very soft organic clay was encountered down to depths of 10 to 12 m, with vane shear strengths of 11 to 46 kPa. SPT resistances varied from 1 to 3 blows/foot. Beneath the organic clay, medium to stiff clay and sandy clay was encountered down to between 17 and 20 m depth with SPT blow counts of 5 to 15. Below this, medium dense to dense clean sands and clayey sands occasionally interbedded with thin sandy clay layers were found down to the depths sampled. SPT resistances in the sandy stratum ranged between 14 and 30 blows/foot. In Borings HHF1, HHF2 and HHF3, an intermediate 10 to 4 m thick layer of very stiff to hard clay or sandy clay was found at 37 to 43 m with SPT resistances of 20 to 44 blows/foot.

Required pile tip elevations are given in Appendix 2.10. For driven 450 mm piles, adequate bearing can be derived from the upper medium dense to dense sandy stratum, and tip elevations vary from 24 to 27 m. The bored piles need to be taken deeper and founded in the lower sand layers. Here tip elevations of between 37 and 47 m have been estimated for the 1000 and 1500 mm piles, the larger piles being founded about 1 m below the smaller ones.

Potential negative friction loads of 430 to 530 kN were estimated for the 450 mm driven piles, 760 to 930 kN for the 1000 mm bored piles and 1,140 to 1,390 kN for the 1500 mm bored piles.

4.11 Footbridges

Ten footbridges have been investigated; three at the NH1 Interchange, four across the Ben Nghe Canal and three at the Hanoi Highway Interchange. At each footbridge site, two borings were made to depths of between 30 and 60 m.

The subsoil conditions for the six footbridges at the two interchanges are similar to the conditions described for the main interchange structures in 4.1 and 4.10 above. The subsoil conditions for the four footbridges across the Ben Nghe Canal are similar to those which have been described for the Cha Va and Calmette bridges.

Smaller piles than those adopted for the major bridges have been selected for the footbridges: 350 mm driven piles and 750 mm and 1000 mm bored piles. Charts showing the pile bearing capacities are given for each bridge site in Appendix 3.1 to 3.10. The required pile tip elevations are given in Table 3.

At the NH1 interchange, the required tip elevations were estimated to vary from 32 m to 42 m for the 350 mm driven piles and from 57 m to 64 m for the bored piles. Along the Ben Nghe Canal, the tip elevations ranged between 28 m and 45 m for the driven piles and between 38 m and 55 m for the bored piles. At the Hanoi Highway Intersection, the driven piles need to be taken down to between 19 and 31 m and the bored piles to between 31 m and 46 m.

Table 3 also gives estimates of potential negative friction loads. These were found to be most critical at the NH1 Interchange and at May Ruou where the soft organic clay layer is deepest. Here, negative friction loads of 700 to 1,550 kN were estimated for the 350 mm driven piles and 1,220 to 2,680 kN for the 1000 mm bored piles. The other Ben Nghe footbridges had little or no negative friction forces. At the Hanoi Highway, the negative friction loads were estimated to range between 300 and 625 kN for the driven piles and 625 and 990 kN for the bored piles.

Table 2 - Major Bridges: estimated pile tip elevations

Table 3 - Footbridges: estimated pile tip elevations

5 References:

1. Meyerhof G.G. (1956), Penetration tests and bearing capacity of cohesionless soils, JSMF, Proc. ASCE, 82, No. SM-1, pp 866-1 to 866-19.

2. Construction & Irrigation Services Company, Investigation & Design Enterprise (1997), Soil Investigation Report on Saigon River Crossing, for Maunsell Vietnam.

3. US Army Corps of Engineers, Bearing Capacity of Soils, Manual EM 1110-1-1905, October 1992.

4. Tokimatsu and Seed (1984), Simplified Procedure for the Evaluation of Settlements in Sands due to Earthquake Shaking, Report No. UCB/EERC-84/16, University of California, Berkeley.

5. Meyerhof G.G. (1976), Bearing Capacity and Settlement of Pile Foundations, ASCE Journal of the Geotechnical Division, Vol. 102, G73, pp 197 228.

6. Leonards G.A. (1962), Foundation Engineering, McGraw-Hill Book Company.

7. US Navy, Naval Facilities Engineering Command, Foundations and Earth Structures, Manual DM 7.02, September 1986.

8. Hsai-Yang Fang (1991), Foundation Engineering Handbook, Van Nostrand Reinhold.

9. California Department of Transportation, Caltrans (2000), Bridge Design Specifications, Section 4 Foundations.

10. US Army Corps of Engineers, Design of Pile Foundations, Manual EM 1110-2-2906, January 1991.

11. Tomlinson M.J. (1957), The adhesion of piles driven in clay soils, Proc. 4th ICSMFE, London, pp 66 71.

12. Saigon East West Highway Project, Reports on Soil Investigation,

Package 1A,

Package 1B,

Package 2A,

Package 2C, the Consultants, January April 2002.

Figure 7, Curve C

SAIGON EAST WEST HIGHWAY

FINAL REPORT

PILE FOUNDATIONS

W. HOWKINS

April 2002

EMBED Excel.Sheet.8

EMBED Excel.Sheet.8

EMBED Word.Picture.8

EMBED Excel.Sheet.8

EMBED Excel.Sheet.8

EMBED Excel.Sheet.8

Curve A

Curve D

The measured compressive strengths have been halved to give undrained shear strength.

PAGE H:\Geotechnical\Soils & Materials Design\Bridge foundations\Report on piled foundations.doc15

_1079748932.xlsChart1

1

0.96

0.75

0.5

0.475

0.37

0.325

0.325

0.325

0.325

0.325

Tomlin

Undrained shear strength - Su - kPa

Adhesion factor - Fa

Fa = -6.28E-08Su3 + 4.56E-05Su2 - 1.08E-02Su + 1.156

BC calc

LG1

4500+

Bored(b)/driven(d)d

Pile width=0.45m0.5

As=1.800m2/m1.8

Ap=0.203m20.2

Depth to bearing stratum

56.0

Radian factor0.0175Qp =Ap. 400. NQp =Ap.qp = Ap.c.NcQp =Ap. pt'.Nq

Qs =S (DL.s.2.N)Qs =S (DL.s.Ca)Qs =S (DL.s.p0'.K.tand)

1234567891011121314151617181920212223242526272829

StrataSoilsub. uwEff. o'burdenCrit. o'burdenDcritDepthNN'N*Impirical FormulaeCohesive strataGranular strataStatic Bearing Capacities

Depthstratag'po'poc'fieldcorr.designDQsQsQpQultCuFaCaDQsQpf 'K.tandNqDQsQpDQsQsQpQult

mt/m3kPakPamm:(blows/ft)blows/ftblows/ftkNkNkNkNkPakPakNkNdegkNkNkNkNkNkN

max =776max =2228

0OH0.00.0-0--0.00000.00-0000

OH1.626.11.0606-0.00000.00-0000

OH1.4019.04.3202-0.00000.00-0000

OH1.4042.610.3202-0.00000.00-0000

OH1.4066.116.3202-0.00000.00-0000

OH1.4580.719.6303-0.00000.00-0000

OH01.45105.925.3303-0.00000.00-0000

OH1.45132.431.3303-0.00000.00-0000

OH1.45158.937.3303-0.00000.00-0000

41.7OH1.45178.341.7303-0.00000.00-0000

SWg1.79185.342.61201249499721021-0.00000.0030.60.2222658436565843908

43.2SWg1.79190.043.21201232819721053-0.0000030.60.22224486444110864974

CHc2.14213.445.348048454535388844233000.3398369547-0.000003694785471025

CHc2.13235.547.346046414949372646752880.3393336524-0.000003368155241338

CHc2.09257.049.3400403601309324045492500.3381293456-0.0000029311074561563

CHc2.06277.751.3350353151624283544592190.3371256399-0.0000025613633991762

CHc1.98296.953.3250252251849202538741560.4672259285-0.0000025916222851906

CHc1.92314.955.3200201802029162036491250.4759211228-0.0000021118332282061

56CHc1.92321.256.020020632092162037121250.475974228-0.000007419072282135Lc/B

SWg2.10335.3335.362.857.341041240233133215652-0.0000039.02.056216052228160535122228574038.95698

SWg2.10356.9356.962.959.342042378270934026111-0.0000039.22.1771278822282788630022288528

SWg2.09378.3378.362.661.340040360306932406309-0.0000038.71.93622625222826258925222811153

SWg2.09399.8392.462.663.340040360342932406669-0.0000038.71.936227222228272211648222813875

SWg2.10421.4396.262.965.342042378380734027209-0.0000039.22.177130952228309514742222816970

340.5771223167

y = 3E-15x9.2999

380.5408757128

phiNqLc/B = 0.5538e0.0848phi

207.4y = 0.5538e0.0848x

218.3

229.2

2310.2

2411.4

2512.7

2614.2

2715.9

2817.8

2920.0

3022.5

3125.3

3228.5

3332.2

3436.5

3541.4

3647.2

3753.8

3861.5

3970.6

4081.3

&CLO GOM BRIDGE - PILE CAPACITIES

&L&6&F &D

BC calc

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

&CLO GOM BRIDGE - LG1

&L&6&F &D

Qs

Qp

Qs'

Qp'

Qu'

Qu

Ultimate bearing capacity - kN

Depth - m

Pile Capacities -

SPT

Peck Hanson & Thornburn (1953)

Nf

1030.030.0

2033.033.1

3036.036.0

4038.738.7

5041.041.0

6042.742.8

7044.044.0

Ncu

212.512.5

42525

85050

16100100

32200200

William Howkins:COE EM 1110, p5-6

William Howkins:Carter, Geot. Eng. Manual, Sheet 10-4

SPT

0

0

0

0

0

0

0

N - blows/ft

Friction angle

BC factors

0

0

0

0

0

N - blows/ft

Cu - kPa

SPT vs Cu

piles

Bearing Capacity factors for shallow foundations (Chen)

ffNqNqbNq tomlinsonNcNg

degreesradiansCaltrans

001.001.05.1415930

0.010000.001.000.01.05.140.00

10.021.090.01.15.380.07

20.031.200.01.25.630.16

30.051.310.01.35.900.25

40.071.430.01.56.190.35

50.091.570.01.66.490.47

60.101.720.01.86.810.60

70.121.880.02.07.160.74

80.142.060.02.27.530.91

90.162.250.02.47.921.10

100.172.470.02.78.341.31

110.192.710.03.08.801.56

120.212.970.03.39.281.84

130.233.260.03.69.812.16

140.243.590.04.010.372.52

150.263.940.14.410.982.94

160.284.340.14.911.633.42

170.304.770.15.512.343.98

180.315.260.26.013.104.61

190.335.800.36.713.935.35

200.356.400.57.414.836.20

210.377.070.78.315.817.18

220.387.821.19.216.888.32

230.408.661.51018.059.64

240.429.602.11119.3211.17

250.4410.663.01320.7212.96

260.4511.854.11422.2515.05

270.4713.205.51623.9417.49

280.4914.727.31825.8020.35

290.5116.449.72027.8623.71

300.5218.40132230.1427.66

310.5420.63172532.6732.33

320.5623.18212935.4937.85

330.5826.09273238.6444.40

340.5929.44353742.1652.18

350.6133.30444146.1261.47

360.6337.75554750.5972.60

370.6542.92685455.6385.95

380.6648.93846261.35102.05

390.6855.961047167.87121.53

400.7064.201278175.31145.19

410.7273.901559483.86174.06

420.7385.3718810993.71209.44

430.7599.01227126105.11253.00

440.77115.31272148118.37306.92

450.79134.87326173133.87374.03

460.80158.50388204152.10458.02

470.82187.21461242173.64563.82

480.84222.30546288199.26697.94

490.86265.50644345229.92869.18

500.87319.06756415266.881089.48

510.89385.98886311.751375.17

520.91470.301035366.661748.90

530.93577.501205434.422242.37

540.94715.071399518.802900.51

550.96893.481620624.923787.81

560.981127.441871759.794998.13

570.991437.962155933.176670.09

581.011855.5224761158.839011.68

591.032425.0828391456.5412340.45

601.053214.1432471855.1017150.34

Terzaghi - shallow foundations

015.8

103.29.51

208174.5

30253721

4010093130

Meyerhof - shallow foundationsBerezantsev - pilesL/B = 20L/B = 70

015.5fNqbNqb

102.582610

15410.51.2291710

206.5142.9302013

30202915355245

40707310040140130

Tomlinson - pilesVesicUSNavy - piled foundations

fNqNcNqfNq

0.0011.05.712610

102.79.612815

154.412.913021

207.417.723125

2512.725.123229

3022.537.243335

3541.457.8103442

4081.395.7413550

3662

3777

3896

39120

40145

q0 = cNcscdc + qNqsqdq + gBNgsgdg

c is the soil cohesion

q0 is the footing contact pressure

q is the effective soil overburden pressure at the footing depth

g is the unit weight of the soil (effective unit weight when FL below WL)

D, B is the footing depth and width

Brinch Hansen factors:

sc = 1 + B/L . Nq/Ncdc = 1 + 0.4D/B for f = 0

sq = 1 + B/L . tanfdc = dq - (1 - dq)/(Nc.tanf ) for f > 0

sg = 1 - 0.4B/Ldq = 1 + 2tanf(1-sinf)2.D/B

dg = 1

Cu/p = 0.11 + 0.0037PI(Skempton 1954)

Skempton

Nc from graphNc trendline

D/Bvery longsquarevery longsquare

05.1406.1375.1406.137

15.8006.9255.8426.975

26.4007.6426.3817.619

47.1008.4777.0788.452

67.4008.8367.4198.858

87.5509.0157.5519.016

107.6009.0747.5869.058

127.6009.0747.5959.069

cuAs

01

251

501

750.84375

1000.6875

1250.53125

1500.375

1750.375

2000.375

2250.375

2500.375

Adhesion - Tomlinson

CuCaCa/Cu

psfkPapsf

25011.972501

50023.944800.96

100047.887500.75

185088.5780.5

200095.769500.475

1400.37

4000191.5213000.325

2000.325

2200.325

2300.325

2500.325

30

31.80.3

320.07

33

340.6

35

360.960.25

37

381.6

38.30.5

fLc/By = 0.5538e0.0848x

71

3410

4525

piles

000000000

000000000

000000000

000000000

00000000

000000

0000

0000

0000

0000

0000

0000

0000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

000

Nc

Nq

Ng

Nq

Nc

Ng

Nq Terzaghi

Nct

Ngt

Nqm

Ncm

Nqn

Friction angle - f - degrees

Nq, Nc, Ng

Bearing Capacity Factors

D/B

Nc

Bearing Capacity Factor Nc

0

0

0

0

0

0

0

0

0

0

0

Tomlin

Undrained shear strength - Su - kPa

Adhesion factor - Fa

Fa = -6.28E-08Su3 + 4.56E-05Su2 - 1.08E-02Su + 1.156

00

00

00

00

00

00

00

00

00

Ng

Nq

Nq

Nqt

Nqm

Nqn

Tomlinson

Friction angle - f - degrees

Nq, Nc, Ng

Bearing Capacity Factors

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Driven piles

Bored piles

Friction angle

Shaft friction factor - beta

Shaft friction factors

PILE DESIGN

Pile detailsSoil parameters1g/cm31000kg/m3

Square (S)/Circular (C)S

Driven (d) / Bored (b)b

Width/diameter of pile0.45mg1.80t/m31lb/in327.68t/m3

Foundation depth30.00mg'0.89t/m31lb/ft316.02kg/m3

Depth to water table2.44mCutip500.0kPa1bar100kPa

Depth of soft soil - hs10mCushaft250kPa1kp/cm2 (atm)98.07kPa

Area of pile - Ap0.203m2c'0.0kPa1t/m29.807kPa

Circumference of pile - s1.8mf'34.5deg1ton/ft2 (US)95.76kPa

1ksf47.88kPa

1. Cohesive soils: undrained conditionf' =0Nc9.00

Nq1.00

Ng5.14

pt' =283.71kPa

Qp =Ap.qp = Ap.c.Nc =911.25kN

Qs =S (DL.s.as.Cus)3050.31kPa

Qall= (Qp + Qs)/2.5 =1584.62

= Qp/3 + Qs/1.5 =2337.29

DLCusFaDQsQs

5.0045.000.77310.02y = -6E-08x3 + 5E-05x2 - 0.0108x + 1.1557

7.5060.000.67546.54

12.50300.000.332193.75

3050.31

2. Granular soils: drained conditionc' =0.0kPaNcd0.00

f' =-degNqd0.00

Ngd0.00

Qp =Ap.qp = Ap. pt'.Nq =0kN

qp =0.00=0.00kPa

Qs =S (DL.s.p0'.K.tand)

KdKtan(d)

Driven1.50000

Bored0.5-0

Source: US, COE

Friction angle

Lc/B

y = 0.5538e0.0848x

0

0

0

0

0

0

_1080025953.doc

Bridge

Lo Gom

Boring

LG1

Station

4+501

Bored(b)/driven(d)

D

Static formulae: granula strata

Pile width

B

0.45

m

Empirical formulae:

Static formulae: cohesive strata

Q

t

= At. pt'.Nq (driven piles)

Depth soft soil Ds

41.7

m

Q

t

= A

t

. m. N

Q

t

= At.qt = At.9.c

Q

t

= At. pt'.Nqb (bored piles)

Critical depth Dc

50.7

m

Radian factor

0.02

Qs =

(

L.A

s

.n.N)

Q

s

=

(

L.As.Ca)

Q

L

= 48.At.N

qp

.tan

'

Shaft area

A

s

1.80

m

2

/m

m

400

Ca = Su.Fa

Qs =

(

L.As.p

0

'.K.tan

)

Pile area

A

t

0.20

m

2

n

2

Shaft resist. factorr

F

fa

1.00

Depth

N

Strata

unit wt

Eff.o'burden

p

design

N

60

N'

N*

Su

Ad. factor

'

field

Depth

g

p

o

'

corr.

design

Fa

DQ

s

Q

s

Q

t

Qult

DQ

n

Q

n

DQ

s

Q

t

K.tand

DQ

s

N

q

N

qp

N

qb

Q

t

Q

L

DQ

s

Q

s

Q

t

Qult

m:

(blows/ft)

m

t/m3

kPa

kPa

blows/ft

blows/ft

blows/ft

kPa

deg

kN

kN

kN

kN

kN

kN

kN

kN

kN

kN

kN

kN

kN

kN

kN

max =

max =

max =

2227.5

0.0

-

0

F

6.50

1.5

6

F

1.90

19.74

19.74

12

-

6

50

0.72

-

0

0

0

0

97

97

0

0

0

0

4.15

2

OH

1.45

31.43

31.43

3

-

2

30

0.87

-

0

0

0

0

125

222

0

0

0

0

6

2

OH

1.45

39.60

39.60

3

-

2

30

0.87

-

0

0

0

0

87

309

0

0

0

0

8

1

OH

1.45

48.42

48.42

1

-

1

25

0.91

-

0

0

0

0

82

391

0

0

0

0

10

2

OH

1.45

57.25

57.25

2

-

2

30

0.87

-

0

0

0

0

94

485

0

0

0

0

12

1

OH

1.45

66.08

66.08

1

-

1

25

0.91

-

0

0

0

0

82

568

0

0

0

0

14

2

OH

1.45

74.90

74.90

2

-

2

30

0.87

-

0

0

0

0

94

662

0

0

0

0

16

2

OH

1.45

83.73

83.73

2

-

2

30

0.87

-

0

0

0

0

94

756

0

0

0

0

18

2

OH

1.45

92.56

92.56

2

-

2

30

0.87

-

0

0

0

0

94

850

0

0

0

0

19.3

3

OH

1.45

98.30

98.30

3

-

3

35

0.83

-

0

0

0

0

68

918

0

0

0

0

21.3

3

OH

1.45

107.13

107.13

3

-

3

35

0.83

-

0

0

0

0

105

1023

0

0

0

0

23.3

3

OH

1.45

115.97

115.97

3

-

3

35

0.83

-

0

0

0

0

105

1127

0

0

0

0

25

2

OH

1.45

123.47

123.47

2

-

2

30

0.87

-

0

0

0

0

80

1207

0

0

0

0

27

3

OH

1.45

132.31

132.31

2

-

3

35

0.83

-

0

0

0

0

105

1312

0

0

0

0

29

2

OH

1.45

141.13

141.13

2

-

2

30

0.87

-

0

0

0

0

94

1406

0

0

0

0

31

3

OH

1.45

149.97

149.97

2

-

3

35

0.83

-

0

0

0

0

105

1511

0

0

0

0

33

3

OH

1.45

158.80

158.80

2

-

3

35

0.83

-

0

0

0

0

105

1615

0

0

0

0

35

3

OH

1.45

167.64

167.64

2

-

3

35

0.83

-

0

0

0

0

105

1720

0

0

0

0

37

3

OH

1.45

176.47

176.47

2

-

3

35

0.83

-

0

0

0

0

105

1825

0

0

0

0

39

2

OH

1.45

185.30

185.30

1

-

2

30

0.87

-

0

0

0

0

94

1919

0

0

0

0

41

3

OH

1.45

194.13

194.13

2

-

3

35

0.83

-

0

0

0

0

105

2023

0

0

0

0

42.3

12

SW

G

1.79

204.26

204.26

8

-

12

-

-

33.2

56

56

972

1028

-

-

0.37

178

41

106

26.8

1711

674

178

178

1711

1889

45

48

CH

C

2.14

234.37

234.37

30

-

48

260

0.33

-

411

467

474

941

-

-

411

474

411

588

474

1062

47

46

CH

C

2.13

256.48

256.48

28

-

46

250

0.33

-

293

759

456

1215

-

-

293

456

293

881

456

1337

49

40

CH

C

2.09

277.90

277.90

23

-

40

220

0.33

-

257

1017

401

1418

-

-

257

401

257

1138

401

1539

51

35

CH

C

2.06

298.68

277.90

20

-

35

195

0.32

-

223

1240

355

1595

-

-

223

355

223

1362

355

1717

53

25

CL

C

1.98

317.82

277.90

14

-

25

145

0.36

-

186

1426

264

1691

-

-

186

264

186

1548

264

1812

55

20

CL

C

1.92

335.87

277.90

11

-

20

120

0.41

-

176

1602

219

1821

-

-

176

219

176

1724

219

1943

57

41

SW

G

2.10

357.42

277.90

21

-

41

-

-

37.2

295

1898

3321

5219

-

-

0.42

424

73

208

44.2

4104

1536

424

2148

4104

6252

59

42

SW

G

2.10

379.08

277.90

21

-

42

-

-

37.2

302

2200

3402

5602

-

-

0.42

424

73

208

44.1

4096

1532

424

2572

4096

6668

61

40

SW

G

2.09

400.50

277.90

20

-

40

-

-

36.9

288

2488

3240

5728

-

-

0.42

420

70

197

42.4

3916

1437

420

2992

3916

6908

63

40

SW

G

2.09

421.93

277.90

19

-

40

-

-

36.8

288

2776

3240

6016

-

-

0.42

419

69

193

41.9

3860

1407

419

3410

3860

7271

65

42

SW

G

2.10

443.59

277.90

20

-

42

-

-

36.9

302

3078

3402

6480

-

-

0.42

420

70

197

42.4

3921

1439

420

3830

3921

7751

strata

Soil

Empirical Formulae

Ngtv. friction

Cohesive strata

Granular strata

Static Bearing Capacities

Lo Gom Bridge

45x45cm driven piles

_1079513551.xlsChart1

1.6

1.3

1

0.7

0.55

0.5

Overburden pressure p - kPa

Correction factor - CN .

SPT Depth Correction Factor Cn

Cn = 7.6873.p-0.4591

COE

LG1

4500+

Bored(b)/driven(d)d

Pile width=0.45m0.45

As=1.800m2/m

Ap=0.203m2

Radian factor0.0175Qp =Ap. 400. NQp =Ap.qp = Ap.c.NcQp =Ap. pt'.Nq

Qs =S (DL.s.2.N)Qs =S (DL.s.Ca)Qs =S (DL.s.p0'.K.tand)

StrataSoilsub. uwEff. o'burdenDepthCritical depthNN'N*Impirical FormulaeCohesive strataGranular strataStatic Bearing Capacities

Depthstratag'po'pc'fieldcorr.designDQsQsQpQultCuFaCaDQsQpf 'K.tandK0.sindNqDQsbDQsnQpDQsQsQpQult

mm:(blows/ft)blows/ftblows/ftkNkNkNkNkPakPakNkNdegkNkNkNkNkNkNkN

max =776max =2228

0OH0.000.0-0--0.00000.00-0.0000

OH1.626.101.0606-0.00000.00-0.0000

OH1.4019.054.3202-0.00000.00-0.0000

OH1.4042.5810.3202-0.00000.00-0.000017.5

OH1.4066.1216.3202-0.00000.00-0.0000

OH1.4580.7019.6303-0.00000.00-0.0000

OH01.45105.8825.3303-0.00000.00-0.0000

OH1.45132.3831.3303-0.00000.00-0.0000

OH1.45158.8937.3303-0.00000.00-0.0000

41.7OH1.45178.3241.7303-0.00000.00-0.00.00.00

SWg1.79185.3342.67.41201239399721011-0.00000.0030.60.40.558.5127160337127127337464

43.2SWg1.79190.0043.27.41201226659721037-0.0000030.60.40.558.58711033787214337551

CHc2.14213.4345.348048363428388843163000.3398369547-0.000003695835471129

CHc2.13235.5347.346046331759372644852880.3393336524-0.000003369195241443

CHc2.09256.9649.3400402881047324042872500.3381293456-0.0000029312114561667

CHc2.06277.7351.3350352521299283541342190.3371256399-0.0000025614673991866

CHc1.98296.8753.3250251801479202535041560.4672259285-0.0000025917262852011

CHc1.92314.9355.3200201441623162032431250.4759211228-0.0000021119382282165

56CHc1.92321.2556.020020501673162032931250.475974228-0.00.000.007420122282239

SWg2.10335.2557.315.041041192186533215186-0.0000039.01.92.02417027461892746275818924650

SWg2.10356.9159.315.342042302216834025570-0.0000039.22.02.12871176123222781232399022786268

SWg2.09378.3461.314.740040288245632405696-0.0000038.71.81.9241991106918761069505918766934

SWg2.09399.7663.314.740040288274432405984-0.0000038.71.81.9241991106918761069612818768003

SWg2.10421.4265.315.342042302304634026448-0.0000039.22.02.12871176123222781232736022789638

350.68675156911892.4554386041

phiNqNqp

20710

21812

22914

231017

241120

251324

261429

271634

281841

292049

302259

312570

322983

333299

3437119

3541142

3647169

3754202

3862241

3971287

4081343

COE

000000

000001

000004.3

0000010.3

0000016.3

0000019.6

0000025.3

0000031.3

0000037.3

0000041.7

0000042.6

0000043.2

0000045.3

0000047.3

0000049.3

0000051.3

0000053.3

0000055.3

0000056

0000057.3

0000059.3

0000061.3

0000063.3

0000065.3

&CLO GOM BRIDGE - LG1

&L&6&F &D

SW

SW

CH

OH

Qs

Qp

Qu

Qs'

Qp'

Qu'

Ultimate bearing capacity - kN

Depth - m

45 x 45 cm driven piles

BC calc

LG1

4500+

Bored(b)/driven(d)d

Pile width=0.45m0.45

As=1.800m2/m

Ap=0.203m2

Radian factor0.0175Qp =Ap. 400. NQp =Ap.qp = Ap.c.NcQp =Ap. pt'.Nq

Qs =S (DL.s.2.N)Qs =S (DL.s.Ca)Qs =S (DL.s.p0'.K.tand)

StrataSoilsub. uwEff. o'burdenDepthNN'N*Impirical FormulaeCohesive strataGranular strataStatic Bearing Capacities

Depthstratag'po'fieldcorr.designDQsQsQpQultCuFaCaDQsQpf 'K.tandNqDQsQpDQsQsQpQult

mm:(blows/ft)blows/ftblows/ftkNkNkNkNkPakPakNkNdegkNkNkNkNkNkN

max =776max =2228

0OH0.000.0-0--0.00000.00-0.0000

OH1.626.101.0606-0.00000.00-0.0000

OH1.4019.054.3202-0.00000.00-0.0000

OH1.4042.5810.3202-0.00000.00-0.0000

OH1.4066.1216.3202-0.00000.00-0.0000

OH1.4580.7019.6303-0.00000.00-0.0000

OH01.45105.8825.3303-0.00000.00-0.0000

OH1.45132.3831.3303-0.00000.00-0.0000

OH1.45158.8937.3303-0.00000.00-0.0000

41.7OH1.45178.3241.7303-0.00000.00-0.0000

SWg1.79185.3342.61201239399721011-0.00000.0030.60.422127843127127843970

43.2SWg1.79190.0043.21201226659721037-0.0000030.60.42287864872148641078

CHc2.14213.4345.348048363428388843163000.3398369547-0.00003695835471129

CHc2.13235.5347.346046331759372644852880.3393336524-0.00003369195241443

CHc2.09256.9649.3400402881047324042872500.3381293456-0.000029312114561667

CHc2.06277.7351.3350352521299283541342190.3371256399-0.000025614673991866

CHc1.98296.8753.3250251801479202535041560.4672259285-0.000025917262852011

CHc1.92314.9355.3200201441623162032431250.4759211228-0.000021119382282165

56CHc1.92321.2556.020020501673162032931250.475974228-0.00007420122282239

SWg2.10335.2557.341041192186533215186-0.0000039.01.962145922281459347022285698

SWg2.10356.9159.342042302216834025570-0.0000039.22.071253322282533600422288231

SWg2.09378.3461.340040288245632405696-0.0000038.71.8622386222823868389222810617

SWg2.09399.7663.340040288274432405984-0.0000038.71.86225212228252110910222813137

SWg2.10421.4265.342042302304634026448-0.0000039.22.07129912228299113901222816129

350.6867515691

phiNqNqp

207

218

229

2310

2411

2513

2614

2716

2818

2920

302259

312570

322983

333299

3437119

3541142

3647169

3754202

3862241

3971287

4081343

William Howkins:COE EM 1110, p5-6

William Howkins:Carter, Geot. Eng. Manual, Sheet 10-4

&CLO GOM BRIDGE - PILE CAPACITIES

&L&6&F &D

BC calc

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

&CLO GOM BRIDGE - LG1

&L&6&F &D

SW

SW

CH

OH

Qs

Qp

Qu

Qs'

Qp'

Qu'

Ultimate bearing capacity - kN

Depth - m

45 x 45 cm driven piles

SPT

Peck Hanson & Thornburn (1953)

Nf

1030.030.0

2033.033.1

3036.036.0

4038.738.7

5041.041.0

6042.742.8

7044.044.0

Ncu

212.512.5

42525

85050

16100100

32200200

SPT depth correction

N60 = CER.CN.NSPT

CER. is the enregy correction: 0.75 for pulley and rope.

p' (ksf)p (kPa)CNCurve

0.628.71.61.65

147.91.31.30

295.810.95

4191.50.70.69

6287.30.550.57

8383.00.50.50

CN = 7.6873.p-0.4591

N60f

43030.4

103534.1

303838.6

504140.7

William Howkins:COE EM 1110, p5-6

William Howkins:Carter, Geot. Eng. Manual, Sheet 10-4

William Howkins:Meyerhof (high), ref EM1110-1, fig 5-15.

SPT

0

0

0

0

0

0

0

N - blows/ft

Friction angle

BC factors

0

0

0

0

0

N - blows/ft

Cu - kPa

SPT vs Cu

piles

0

0

0

0

0

0

Overburden pressure p - kPa

Correction factor - Cn

SPT Depth Correction Factor Cn

CN = 7.6873.p-0.4591

0

0

0

0

N60 - blows/ft

Friction angle - f

N60 vs. phi

f = 4.1057Ln(N60) + 24.707

Bearing Capacity factors for shallow foundations (Chen)

ffNq ChenNq tomlinsonMeyerhof

degreesradianslowhigh

valuescurve fitvaluescurve fit

0011.01.0

0.010000.001.01.011.0

10.021.11.111.1

20.031.21.211.3

30.051.31.311.5

40.071.41.521.7

50.091.61.61.721.91.9

60.101.71.822.2

70.121.92.022.5

80.142.12.222.8

90.162.32.433.2

100.172.52.72.833.63.7

110.192.73.034.2

120.213.03.334.8

130.233.33.645.5

140.243.64.046.3

150.263.94.44.656.57.2

160.284.34.958.2

170.304.85.569.4

180.315.36.0710.8

190.335.86.7712.4

200.356.47.48.0813.014.3

210.377.18.3916.5

220.387.89.21019.0

230.408.7101122.0

240.429.6111325.4

250.4410.71315.01527.029.4

260.4511.9141634.1

270.4713.2161839.6

280.4914.7182146.1

290.5116.4202453.8

300.5218.42229.52760.062.9

310.5420.6253173.7

320.5623.2293586.5

330.5826.13240101.7

340.5929.43746120.0

350.6133.34155.053140.0141.9

360.6337.84761168.2

370.6542.95471200.1

380.6648.96282238.6

390.6856.07195285.5

400.7064.281110.0112350.0342.8

410.7273.994131413.1

420.7385.4109155499.5

430.7599.0126183606.5

440.77115.3148218739.5

450.79134.9173260.0261820.0905.6

460.80158.52043141114.2

470.82187.22423801377.6

480.84222.32884631712.1

490.86265.53455672139.5

500.87319.14157002689.2

Nq = 0.291e0.1768fNq = 0.319e0.1479f

Tomlinson - pilesVesicfUSNavyBerezantsev - pilesFangfNq MeyerhofCurve fitCurve fitNordlund

fNqNcNqNqNqNqbNtLowHighlowHighNqp

0.0011.05.71DisplacementBoredL/B = 20L/B = 7001.01.0

102.79.61261051051.71.9

154.412.9128157.520102.83.5

207.417.72302110.52013154.66.5

2512.725.12312512.5208.013.01.44

3022.537.24322914.5302515.027.013245.12

3541.457.810333517.53028.060.0275915.3

4081.395.741344221403555.0140.05614243.55

35502552456040112.0350.0118343120

36623145260.0820.0248830400

377738.5

38964810090

3912060

4014572.5140130150

45300

Cu/p = 0.11 + 0.0037PI(Skempton 1954)

Caltrans:Nc = 6.0(1 + 0.2xD/Bt), Nc45

_1069136582.xlsChart2

111.00099748191.000897781050261.00101303541.0012946011

1.91.71.1046813281.0938953717157.55201.10656516191.1381285096

3.52.81.22001642171.1966598112110.510301.22454900831.2954054793

6.54.61.34713080411.30919380472512.515311.3552510981.4745735787

1381.48728066661.43250041252914.51.44301.50013422121.6787912827

27151.64186991471.5676984913517.55.12331.6608473111.9117005888

60281.81246970491.7160378363422115.3401.83925194182.1775066546

140552.00084088071.8789165545502543.55602.0374530352.481071627

3501122.20895978572.05790102656231120362.25783451672.828025398

8202602.43904802012.25474890087738.5400372.503100813.2248965981

2.69360681312.47143562519648382.77632522413.6792678343

2.97545680932.710185128112060393.08100651224.199960038

3.28778422042.973505374814572.51503.42113513074.7972518489

3.6341944783.26422966183003.80127104935.4831412616

4.01877475033.58556468954.22663534916.2716583815

4.44616695713.94114665444.70321832817.1792401402

4.92165325124.3351068595.23790742228.2251803178

5.45125634884.77214864815.83863898419.4321713399

6.04185758825.2576378596.514578874410.8269582226

6.70133622295.79770944657.276337955912.4411299454

7.43873422176.39939352118.13623000614.3120797241

8.26445180077.07076476299.108581353116.4841734785

9.19048010617.821120071710.210103801719.0101757266

10.23067894948.661190435311.460345271921.9529947885

11.40110937089.603394410712.88223622425.3878253603

12.720433156310.662142388514.502754586129.4047872757

14.210394423611.854203059316.353737881934.1121860101

15.896402181413.1991463618.472878948839.6405550682

17.808237612114.719880826320.904951620446.147685308

19.980916047216.443307955923.703325730153.8249048364

22.455741618518.401122218726.931847799862.9049498487

25.281602956920.630793159930.667186141873.6718677772

28.51657183523.17677620735.001768699686.473527639

32.229884369326.092012099240.0474813414101.7374898794

36.504407716629.439792369645.9403470406119.9912249056

41.439726094533.296091491452.8464774185141.8879874855

47.156021114137.752497171960.9696844336168.2400833199

53.798976601242.919911654670.5612714987200.0618464671

61.546012566548.933252702181.9327040904238.6254412278

70.614254200255.957458744595.4721103293285.5336936821

81.270780296664.195206389111.6659115423342.8156664048

93.845886533173.8968914265131.1273746861413.0527875873

108.750364497885.3736230346154.6345765451499.5462828521

126.498169321999.0142589646183.1812690695606.5407991365

147.7363744552115.3079023377218.0455796368739.5249913677

173.2850617619134.8738406263260.8835880121905.6382590468

204.1908743052158.5017131478

241.7995283541187.205864472

287.8548867946222.2995611018

344.6356216114265.497303023

415.1456420799319.0572994482

A

B

C

D

E

F

G

G

F

'A' Meyerhof (high)

'B' Meyerhof (low)

'C' Tomlinson

'D' Terzaghi & Peck

'E' USN driven piles

'F' USN - bored piles

'G' Nordlund

Fang - Nt values

try

try high

Friction angle - f - degrees

Nq

Deep foundations - Bearing Capacity Factor Nq

COE

LG1

4500+

Bored(b)/driven(d)d

Pile width=0.45m0.45

=1.800m2/m

=0.203m2

Radian factor0.0175

Qs =Qs =

StrataSoilsub. uwEff. o'burdenDepthCritical depthNN'N*Impirical FormulaeCohesive strataGranular strataStatic Bearing Capacities

Depthstratafieldcorr.designQpQultCuFaCaQpQpQpQult

mm:(blows/ft)blows/ftblows/ftkNkNkNkNkPakPakNkNdegkNkNkNkNkNkNkN

max =776max =2228

0OH0.000.0-0--0.00000.00-0.0000

OH1.626.101.0606-0.00000.00-0.0000

OH1.4019.054.3202-0.00000.00-0.0000

OH1.4042.5810.3202-0.00000.00-0.000017.5

OH1.4066.1216.3202-0.00000.00-0.0000

OH1.4580.7019.6303-0.00000.00-0.0000

OH01.45105.8825.3303-0.00000.00-0.0000

OH1.45132.3831.3303-0.00000.00-0.0000

OH1.45158.8937.3303-0.00000.00-0.0000

41.7OH1.45178.3241.7303-0.00000.00-0.00.00.00

SWg1.79185.3342.67.41201239399721011-0.00000.0030.60.40.558.5127160337127127337464

43.2SWg1.79190.0043.27.41201226659721037-0.0000030.60.40.558.58711033787214337551

CHc2.14213.4345.348048363428388843163000.3398369547-0.000003695835471129

CHc2.13235.5347.346046331759372644852880.3393336524-0.000003369195241443

CHc2.09256.9649.3400402881047324042872500.3381293456-0.0000029312114561667

CHc2.06277.7351.3350352521299283541342190.3371256399-0.0000025614673991866

CHc1.98296.8753.3250251801479202535041560.4672259285-0.0000025917262852011

CHc1.92314.9355.3200201441623162032431250.4759211228-0.0000021119382282165

56CHc1.92321.2556.020020501673162032931250.475974228-0.00.000.007420122282239

SWg2.10335.2557.315.041041192186533215186-0.0000039.01.92.02417027461892746275818924650

SWg2.10356.9159.315.342042302216834025570-0.0000039.22.02.12871176123222781232399022786268

SWg2.09378.3461.314.740040288245632405696-0.0000038.71.81.9241991106918761069505918766934

SWg2.09399.7663.314.740040288274432405984-0.0000038.71.81.9241991106918761069612818768003

SWg2.10421.4265.315.342042302304634026448-0.0000039.22.02.12871176123222781232736022789638

350.68675156911892.4554386041

phiNqNqp

20710

21812

22914

231017

241120

251324

261429

271634

281841

292049

302259

312570

322983

333299

3437119

3541142

3647169

3754202

3862241

3971287

4081343

COE

000000

000001

000004.3

0000010.3

0000016.3

0000019.6

0000025.3

0000031.3

0000037.3

0000041.7

0000042.6

0000043.2

0000045.3

0000047.3

0000049.3

0000051.3

0000053.3

0000055.3

0000056

0000057.3

0000059.3

0000061.3

0000063.3

0000065.3

&CLO GOM BRIDGE - LG1

&L&6&F &D

SW

SW

CH

OH

Qs

Qp

Qu

Qs'

Qp'

Qu'

Ultimate bearing capacity - kN

Depth - m

45 x 45 cm driven piles

BC calc

LG1

4500+

Bored(b)/driven(d)d

Pile width=0.45m0.45

=1.800m2/m

=0.203m2

Radian factor0.0175

Qs =Qs =

StrataSoilsub. uwEff. o'burdenDepthNN'N*Impirical FormulaeCohesive strataGranular strataStatic Bearing Capacities

Depthstratafieldcorr.designQpQultCuFaCaQpQpQpQult

mm:(blows/ft)blows/ftblows/ftkNkNkNkNkPakPakNkNdegkNkNkNkNkNkN

max =776max =2228

0OH0.000.0-0--0.00000.00-0.0000

OH1.626.101.0606-0.00000.00-0.0000

OH1.4019.054.3202-0.00000.00-0.0000

OH1.4042.5810.3202-0.00000.00-0.0000

OH1.4066.1216.3202-0.00000.00-0.0000

OH1.4580.7019.6303-0.00000.00-0.0000

OH01.45105.8825.3303-0.00000.00-0.0000

OH1.45132.3831.3303-0.00000.00-0.0000

OH1.45158.8937.3303-0.00000.00-0.0000

41.7OH1.45178.3241.7303-0.00000.00-0.0000

SWg1.79185.3342.61201239399721011-0.00000.0030.60.422127843127127843970

43.2SWg1.79190.0043.21201226659721037-0.0000030.60.42287864872148641078

CHc2.14213.4345.348048363428388843163000.3398369547-0.00003695835471129

CHc2.13235.5347.346046331759372644852880.3393336524-0.00003369195241443

CHc2.09256.9649.3400402881047324042872500.3381293456-0.000029312114561667

CHc2.06277.7351.3350352521299283541342190.3371256399-0.000025614673991866

CHc1.98296.8753.3250251801479202535041560.4672259285-0.000025917262852011

CHc1.92314.9355.3200201441623162032431250.4759211228-0.000021119382282165

56CHc1.92321.2556.020020501673162032931250.475974228-0.00007420122282239

SWg2.10335.2557.341041192186533215186-0.0000039.01.962145922281459347022285698

SWg2.10356.9159.342042302216834025570-0.0000039.22.071253322282533600422288231

SWg2.09378.3461.340040288245632405696-0.0000038.71.8622386222823868389222810617

SWg2.09399.7663.340040288274432405984-0.0000038.71.86225212228252110910222813137

SWg2.10421.4265.342042302304634026448-0.0000039.22.07129912228299113901222816129

350.6867515691

phiNqNqp

207

218

229

2310

2411

2513

2614

2716

2818

2920

302259

312570

322983

333299

3437119

3541142

3647169

3754202

3862241

3971287

4081343

William Howkins:COE EM 1110, p5-6

William Howkins:Carter, Geot. Eng. Manual, Sheet 10-4

&CLO GOM BRIDGE - PILE CAPACITIES

&L&6&F &D

BC calc

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

000000

&CLO GOM BRIDGE - LG1

&L&6&F &D

SW

SW

CH

OH

Qs

Qp

Qu

Qs'

Qp'

Qu'

Ultimate bearing capacity - kN

Depth - m

45 x 45 cm driven piles

SPT

Peck Hanson & Thornburn (1953)

Nf

1030.030.0

2033.033.1

3036.036.0

4038.738.7

5041.041.0

6042.742.8

7044.044.0

Ncu

212.512.5

42525

85050

16100100

32200200

SPT depth correction

p' (ksf)p (kPa)Curve

0.628.71.61.65

147.91.31.30

295.810.95

4191.50.70.69

6287.30.550.57

8383.00.50.50

N60f

43030.4

103534.1

303838.6

504140.7

William Howkins:COE EM 1110, p5-6

William Howkins:Carter, Geot. Eng. Manual, Sheet 10-4

William Howkins:Meyerhof (high), ref EM1110-1, fig 5-15.

SPT

N - blows/ft

Friction angle

BC factors

N - blows/ft

Cu - kPa

SPT vs Cu

piles

Overburden pressure p - kPa

Correction factor - Cn

SPT Depth Correction Factor Cn

CN = 7.6873.p-0.4591

N60 - blows/ft

Friction angle - f

f = 4.1057loge(N60) + 24.707

Bearing Capacity factors for shallow foundations (Chen)

ffNq ChenNq tomlinsonMeyerhof

degreesradianslowhigh

valuescurve fitvaluescurve fit

0011.01.0

0.010000.001.01.011.0

10.021.11.111.1

20.031.21.211.3

30.051.31.311.5

40.071.41.521.7

50.091.61.61.721.91.9

60.101.71.822.2

70.121.92.022.5

80.142.12.222.8

90.162.32.433.2

100.172.52.72.833.63.7

110.192.73.034.2

120.213.03.334.8

130.233.33.645.5

140.243.64.046.3

150.263.94.44.656.57.2

160.284.34.958.2

170.304.85.569.4

180.315.36.0710.8

190.335.86.7712.4

200.356.47.48.0813.014.3

210.377.18.3916.5

220.387.89.21019.0

230.408.7101122.0

240.429.6111325.4

250.4410.71315.01527.029.4

260.4511.9141634.1

270.4713.2161839.6

280.4914.7182146.1

290.5116.4202453.8

300.5218.42229.52760.062.9

310.5420.6253173.7

320.5623.2293586.5

330.5826.13240101.7

340.5929.43746120.0

350.6133.34155.053140.0141.9

360.6337.84761168.2

370.6542.95471200.1

380.6648.96282238.6

390.6856.07195285.5

400.7064.281110.0112350.0342.8

410.7273.994131413.1

420.7385.4109155499.5

430.7599.0126183606.5

440.77115.3148218739.5

450.79134.9173260.0261820.0905.6

460.80158.52043141114.2

470.82187.22423801377.6

480.84222.32884631712.1

490.86265.53455672139.5

500.87319.14157002689.2

Tomlinson - pilesVesicfUSNavyBerezantsev - pilesFangfNq MeyerhofCurve fitCurve fitNordlund

fNqNcNqNqNqNqbNtLowHighlowHighNqp

0.0011.05.71DisplacementBoredL/B = 20L/B = 7001.01.0

102.79.61261051051.71.9

154.412.9128157.520102.83.5

207.417.72302110.52013154.66.5

2512.725.12312512.5208.013.01.44

3022.537.24322914.5302515.027.013245.12

3541.457.810333517.53028.060.0275915.3

4081.395.741344221403555.0140.05614243.55

35502552456040112.0350.0118343120

36623145260.0820.0248830400

377738.5

38964810090

3912060

4014572.5140130150

45300

Cu/p = 0.11 + 0.0037PI(Skempton 1954)

Caltrans:Nc = 6.0(1 + 0.2xD/Bt), Nc45

E

_1079512472.xlsChart1

1.12179487181.1782

1.51.2786742538

21.3499618713

31.4504361251

1.52243589741.5217237427

51.5770187147

61.6221979965

71.6603965349

81.693485614

91.7226722503

1.76282051281.748780586

111.7723984486

121.7939598678

141.8321584063

161.8652474854

201.9205424574

251.9758374294

1.92307692312.0210167112

352.0592152496

402.0923043287

452.121490965

2.16346153852.1475993007

552.1712171633

602.1927785825

g = 0.2478.loge(N) + 1.1782

Points from empirical data published by Meyerhof, Ref 1.

SPT 'N' - blows/ft

Unit weight - t/m3 .

Sheet1

Nunit weight

blows/ftt/m3

11.181.12179487180.2478*LN(spt)+1.1782

1.51.28

21.35

31.45

41.521.5224358974

51.58

61.62

71.66

81.69

91.72

101.751.7628205128

111.77

121.79

141.83

161.87

201.92

251.98

302.021.9230769231

352.06

402.09

452.12

502.152.1634615385

552.17

602.19

Sheet1

g = 0.2478.loge(N) + 1.1782

Points from empirical data published by Meyerhof, Ref 1.

SPT 'N' - blows/ft

Unit weight - t/m3

Sheet2

Points from empirical data published by Meyerhof, Ref 1.

Sheet3