THE KUWAITI CODE FOR THE DESIGN OF REINFORCED CONCRETE STRUCTURES

Husain Al-Khaiat, Kuwait University,

37th Conference on OUR WORLD IN CONCRETE & STRUCTURES: 29 - 31 August 2012,

Singapore

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37th Conference on Our World in Concrete & Structures

29-31 August 2012, Singapore

THE KUWAITI CODE FOR THE DESIGN OF REINFORCED CONCRETE STRUCTURES

Husain Al-Khaiat*

*Civil Engineering Department, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait e-mail: <husalkhayat@yahoo.com>

Keywords: Code, Reinforced Concrete, ACI, BS

Abstract. A unified code for the design and construction of concrete structures is essential to develop good engineering practice and to upgrade the construction standards, especially in Kuwait where extreme climatic and subgrade conditions exist. A special code for any country takes effort and time to establish, especially for a small country like Kuwait. Therefore, it was decided to adopt the American Concrete Institute (ACI) code (ACI 318) as the basis for the Kuwait code. The emphasis is on including local experience in this code. The first chapters that deal with materials, durability aspects, and quality control have been slightly modified. The amendments are done to suit the weather, the soil character, and construction experience in Kuwait. The code includes minimum live loads for design. It is hoped that studies and research will lead to continuous updating of the code

.

1 INTRODUCTION

Due to the steady increase of construction projects in the Arabian Gulf states there is an increase in the number of engineering firms and construction companies, thus an increase in the number of engineers employed in the work field. The construction drawings seem to suffer greatly in quality because of the various design codes used from one project to another, and in some cases the usage of numerous codes in the same project due to lack of a national code of design. For that the importance of the existence of a national code of design increases with the presence of engineers of mixed backgrounds in addition to poor workmanship in the building and construction field. Also, the harsh local conditions, such as high weather temperatures, high humidity levels, and great chloride and sulfate rates require high quality designs to achieve strength and overcome loads on buildings in addition to concrete quality able to withstand local conditions of facility sustainability. Therefore it is important to form a national code that sets the standards to ensure the sustainability and safety to avoid failures and durability of structures, which in due part cause human and financial losses. The proposed code of the design of concrete structures, in addition to the new standards of execution of concrete, leads to the sustainability of concrete facilities, thus saving vast amounts of funds that are being used in these projects. The Kuwait code for the design of structures has been adopted as the official code. The code that was selected is highly relatable to the American code ACI 318, with some minor changes and additions in the clauses to make it suitable for Kuwait. It should be noted that the set of codes has been presented to the public or private sectors and consulting firms, and the changes have been made based on the changes suggested by the previously mentioned parties.

Husain Al-Khaiat

This paper presents the importance of the existence of a local code. This paper will further discuss the reasons the American code ACI 318 was chosen as a source for the Kuwait code and what it takes to make the Kuwaiti code successful. This paper will also point out the most important clauses in this code.

2 PURPOSE OF STUDY

The purpose of this study is to draft a national code for the design of reinforced concrete structures, that will be updated periodically based on experiences of usage and supporting research.

3 METHODOLOGY

To draft the code, the following steps have been followed: 1. Surveys for private and public engineering firms and companies and major contracting

companies have been conducted. 2. International codes were reviewed. 3. The suitable code was selected. 4. Changes have been made on the chosen code. 5. The proposed code was sent to private and public engineering firms and companies and major

contracting companies to receive feedback. 6. Seminar were held to present and discuss the proposed code. 7. Amendments have been made on the proposed code based on feedback. 8. The code was presented to the Public Authority for Industry. 9. The code was approved as the official national Kuwait code.

4 VIEWS ON THE TYPE OF CODE

A survey has been prepared to take into consideration the views on the code type wanted. The survey has been sent to all engineering firms, most private and public companies with engineering expertise, and major contracting companies. 43 responses from 35 different institutes have been received, all from major engineering institutes of Kuwait. The results show that 98% see the importance of the existence of a unified code to design the concrete structures. 68% prefer choosing an international code, whilst 32% see the importance of drafting a local national code. Sixty nine percent of the survey participants prefer using the American code. 59% see the importance of making changes and additions to the international code that is used. The results show that 72% of the participants have chosen the English language as the official language of the code because of its dominance in the engineering field in Kuwait.

4.1 Review of internal codes

Major international and regional codes were reviewed. The goal of the study is to choose the appropriate code and assign it as the foundation of the local code, and to choose the clauses to be included and amended in the selected code. The studies have shown that the American code excels above other codes because it has clear development methodology and ongoing updates. Therefore, the American code (ACI 318) was chosen as a base to the national code for the following reasons:

1. The constant and programmed development of the code. 2. The majority of structural engineers have enough knowledge of this code especially since most

engineers are graduates of universities based on the USA system, where the code is being taught.

3. The survey results which indicate that the majority’s approval of using the code.

5 AMENDMENTS ON THE AMERICAN CODE

A team of experts made changes and additions to the American Code to make it more compatible with the local Kuwaiti weather and environmental conditions, also adjusting it to the local experience, putting the survey suggestions and international code descriptions into consideration. More changes should be made on the American Code, and these changes should be based on studies, surveys, and other codes that exist in similar circumstances to those in Kuwait. Samples of the clauses and changes that have been made in the Kuwaiti Code of designing concrete facilities are:

Husain Al-Khaiat

1. The American Concrete Institute Code (ACI 318-02) is adopted as the Kuwait code for Concrete Construction. Modifications and additions to ACI code appear in the following clauses.

2. This code is read in combination with the American Concrete Building Code for 2002 (ACI 318-02).

3. Whenever an ASTM (American Society for Testing and Materials) standard is referenced , the corresponding BS (British Standards) and KSS (Kuwait Specifications & Standards) are also applicable as mentioned in Table 1.

4. Concrete strength can be based on cubes or cylinders. The strength of cubes fcu can be converted to cylinder strength fc' according to Table 5.1.2 (see clause 14).

Add the new following sections:

5. Section 3.3.3: Maximum allowable acid soluble sulfate content SO3 in aggregates should be such that the total sulfate content in the concrete is as given in clause 11, and should not exceed 0.4% by weight.

6. Section 3.4.4:

The limits of accepting water for mixing as well as for curing are as follows: Total dissolved solids < 2000 ppm Suspended solids < 2000 ppm Chlorides as Cl ions < 500 ppm Sulfates as SO3 < 1000 ppm Alkali HCO3 / CO3 < 1000 ppm

Amend the following sections as:

7. Section 3.4.2: Mixing water for pre-stressed concrete or for reinforced concrete including that portion of mixing water contributed in the form of free moisture on aggregates, shall not contain deleterious amounts of chloride ion (See 4.4.1).

8. Section 3.6.3: Calcium Chloride or admixtures containing chloride from other than impurities from admixture ingredients shall not be used in pre-stressed concrete, reinforced concrete, etc.

Change the following Table to:

9. Table 4.4.1:

ACI 222 Chloride Limits, % by weight of cement

WATER SOLUBLE ACID SOLUBLE ASTM 1152C

Test Method STRUCTURE ASTM 1218 or SOXHLET

0.06 0.08 Pre-stressed Concrete

0.08 0.10 Reinforced Concrete Wet Conditions

0.15 0.20 Reinforced Concrete Dry Conditions

Table 1: Maximum chloride ion content for corrosion protection of reinforcement

Add the new following sections:

10. Section 4.5: For reinforced concrete in contact with soil within the capillary rise zone or below groundwater level, effective membrane tanking system shall be used. Special precautions should be taken where water may be introduced at the surface by irrigation, discharge of water, washing down, etc. These requirements are in addition to others in table 4.3.1.

11. Section 4.6: Maximum acid soluble sulfate content SO3 in concrete shall not exceed 4% by mass of cement in the mix. [BS 8110 and BS 5328].

6 SUMMARY AND CONCLUSIONS

A unified code for the design and construction of concrete structures is drafted for Kuwait in order to develop good engineering practice and to upgrade the construction standards especially where extreme climatic and subgrade conditions exist. The ACI 318 code is adopted as the main code with

Husain Al-Khaiat

amendments, deletions and additions to reflect the special conditions of Kuwait. The code requires continuous updating and support from research.

REFERENCES

[1] ACI Committee 318, Code Requirements For Reinforced Concrete (ACI 318-02), American Concrete Institute. Farmington Hills. Mich (2002).

[2] ACI Committee 201, Guide to Durable Concrete (ACI 201.2), American Concrete Institute. Farmington Hills. Mich (1997).

[3] ACI Committee 214, Recommended Practice For Evaluation of Strength Test Results For Concrete (ACI 214), American Concrete Institute. Farmington Hills. Mich (1997).

[4] ACI Committee 222, Corrosion of Metals in Concrete (ACI 222), American Concrete Institute. Farmington Hills. Mich (1996).

[5] British Standard Institution (BS 8110, BS 5328 and other various parts) BSI. London. [6] American Society for Testing and Materials, (various sections) Philadelphia, USA. [7] Kuwait Building Code, Requirements for Reinforced Concrete, National Authority for Industry,

Kuwait (2005).