INSIGHT 03 OPTIMIZATION 67

By automating the structural engineering calculations of standard curtainwall units as part of the pre-sale and pricing phase of a building project, resources are optimized, building material quantities are reduced, and a standardized set of deliverables is developed for the bid proposal presentation. As a bi-product, automated calculations eliminate mistakes caused by human error in standard calcu-lations. The automation of these calculations enables structural engineers to focus on job specific challenges that distinguish Enclos from the competition.

TIME

Throughout the bid process, structural engineers spend a significant amount of time on the design analysis of standard curtainwall elements. The structural engineers sizing of facade elements and the designers mullion section is a somewhat iterative process that is critical to the pre-sale process. If the Studios can reduce the turnaround time of proposals, we are able to bid for more work with the same resources.

STANDARDIZATION

The engineering calculations included in proposals produced by the Studio include unique content for each project. This is not desirable, at least for the standard curtainwall units. Although the added value of the Studio is embedded in the capability to solve nonstandard complex problems, there is no added value in varying the calculation report of standard curtainwall units.

OPTIMIZATION

Market conditions in facade manufacturing are moving into a direction that favor optimized use of material. Labor costs and logistical know-how may sway an owner in awarding a project, but every-thing else being equal, material quantities and associated costs are increasingly becoming a deciding factor. The structural engineer sets the limit of minimum amount of material that can safely support specified loads. The responsibility to optimize material quantities and increase the likelihood of project award rests in the Studios' hands.

GI JSBERT LIBOUREL, P.E.

AUTOMATION OF STANDARD CURTAINWALL CALCULATIONS

marianneRectangle

INSIGHT 03 OPTIMIZATION 69

GEOMETRY

MULLION

MATERIALLOADS

GLASS

COSTING /OPTIMIZATION

CALCULATIONSGEOMETRY

# of connections,parts

diagrams

vertical joint size

horizontal joint size

glass make-up

sections

code checks

loads/materials

moments

deflection

maximum stress

glass make-up

section properties

anchor calcs

glass beads

# of dies

material quantity

dead loads(glass & aluminum)

wind

maintenance

blast

seismic

aluminum(elasticity)

aluminum (shear)

concrete(cubic strength)

centerlines

glass blocks

steelreinforcement

anchor type

ASTM 1300

ESP mulliondatabase

Blast.exe

Windgard

Strand7

anchor checks

mullionoptimization

25

26

27

31

32

33

35

36

38

39

40

37

28

29

30

22

24

18

19

21

14

15

16

17

10

11

12

5

6

7

8

9

1

2

3

4

INPUT OUTPUT

DATABASE MULLIONSDATABASE ANCHORS STRAND7

CALCULATION ENGINE

algorithms

exports datathrough API

lookup functions

GOALS

The goals of the automation effort are:

Reduce the time to size members and produce the report for structural calculations of standard curtainwall units by a factor of 10. This reduction in turnaround time enables Enclos to bid an increased volume of work on an annual basis with the current structural engineering staff.

Standardize the structural calculation output report for standard curtainwall units in Studio proposals.

Optimize material use (glass and aluminum) to enhance the Studios' competitiveness in the marketplace (cost proposition).

SCOPE

Standard curtainwall units (see Figures 3 & 4):

Calculation package for pre-sale purposes to include in the bid proposal package.

Elements span up to five building stories with varying floor-to-floor heights.

Standard anchor types (top of slab and face of slab).

Wind loads and dead loads. Minimum of three vertical mullions. Minimum of two horizontal mullions. Panel material transfers wind loads based

on tributary area. Self-weight of the panels is concentrated

at the setting block locations on the horizontal mullions.

COMPUTER PROGRAM

INPUTS AND OUTPUTS

Computer executable programs generally consist of inputs, a computing engine or process and outputs (see Figure 1).

COMPUTING ENGINE

Enclos uses the Strand7 calculation engine through the Application Programming Interface (API). Strand7 is used to analyze internal forces (i.e., bending moments and shear forces) and deflections of the structure of the curtainwall due to the imposed loads (see Figure 2).

STRAND7

Through the API it is possible to build and analyze a Strand7 model that is parametric without actually opening Strand7 by using a dummy Strand7 model with the following elements:

Nodes Beams Beam releases Plates Load patches with normal distributed

wind load Concentrated loads Supports Material properties Section properties library Rigid links

FIGURE 1Automated workflow production for a standard engineered calculation package for curtainwall units.

FIGURE 2Diagram showing Strand7 API process in the program.

INSIGHT 03 OPTIMIZATION 71

PANEL 19 PANEL 20

PANEL 17 PANEL 18

PANEL 15 PANEL 16

PANEL 13 PANEL 14

PANEL 11 PANEL 12

PANEL 09 PANEL 10

PANEL 07 PANEL 08

PANEL 05 PANEL 06

PANEL 03 PANEL 04

PANEL 01 PANEL 02

PANEL 03 PANEL 04

PANEL 01 PANEL 02

PANEL 01 PANEL 02

PANEL 03 PANEL 04

PANEL 01 PANEL 02

PANEL 05 PANEL 06

20 3419

04

2326

11

3033

18

27

09

45

63

81

06

03 10

07

13

17

14

02 16

38 52

56 70

74 88

0105

0812

15

37

22

41 44

29

48 51

36

24

21 28

25

31

35

32

55

40

59 62

47

6669

54

42

39 46

43

49

53

50

73

58

77 80

65

84 87

72

60

57 64

61

67

71

68

76 83 90

78

75 82

79

85

89

86

91 92

20 2819

04

21 23

11

25 27

18

24

0906

03 10

07

13

17

14

02 1601 05 08 12 15

22 26

15 2314 16 18 20 22

19

0705

03 08

10

13

02 1201 04 06 09 11

17 21

25 3324

05

26 28

14

30 32

23

29

1107

03

12

09

16

21

18

02 2001 06 10 15 19

27 31

04 13 22

08 17

UNIT 1A

UNIT 2A

UNIT 3A

UNIT 2B

B Bbbb b

a

a

L1

L2

a

L3

L4

a

L5

L6

a

L7

L8

L9

L10

B Bbbb b

a

a

L1

L2

B Bbbb b

a

a

L1

B Bbbb b

a

a

L1

L3

L2

50

51

58

59

54

40 00

28 36

17 25

03 13

39 4743

27 3531

16 2420

02 1207

04 1409

18 2622

29 3733

41 4845

52 6056

21

08

32

44

55

17 21

03 13

16 2018

02 1207

04 1409

19

08

14 18

03 11

13 1715

02 1006

16

07

20 24

03 15

19 2321

02 1408

05 1711

22

09

04 1610

30 3834

42 4946

53 6157

19 2623

05 1510

01 1106

05 1510

01 1106

04 1208

01 0905

06 1812

01 1307

mullions

nodes

anchors

glass

KEY

The elements in the dummy model dont have the correct values since the model can be populated with the correct values by copy-pasting the correct values into the model through the Strand7 API. After the correct values are thus imported the model is built and analyzed.

GEOMETRY INPUT

The geometry of standard curtainwall units falls into two categories.

SINGLE-SPAN UNITS

For single-span units, the three types displayed in Figure 3 are considered. The input consists of the length (L), the width (B) of the panels and the location of the setting blocks. In the future, more types can be developed, but for the first stage of the automation process the three types depicted above are developed. This is repre-sented by Input Option 2. Input of the node coordinates by the user is deemed to be cumber-some and error prone. The node coordinates, beams, etc. are generated in the calculation engine before the Strand7 model is built by the aforementioned process.

A toggle function in the program enables the choice between single-span Types 1A, 2A and 3A, or the multi-span Types 1B, 2B and 3B.

MULTI-SPAN UNITS

For the multi-span unit (Type 2B) in Figure 4, the input consist of the lengths (L1 through L10), the width (B) of the panels, the location of the stack joint (a), and the location of the setting blocks (b). Type 1B and 3B have similar input. The difference between the types is the number of panels. Type 1B has inputs for L1 through L5 and type 3B has inputs for L1 through L15.

In the future more types will be developed, but the first stage of the automation process consists of these three types.

RESULTS

CURRENT STATUS

Enclos chose to produce an executable file scripted in C# with several user input screens. Results include:

Creating a Strand7 model with the correct geometry for Type 2B walls that is both quick and effective.

A database/library of previously designed mullion sections that can be referenced and continually added to.

Pre-processing of wind loads in accordance with ASCE7-2010.

Post-processing of mullion sections as part of standard report output.

Saving the Strand7 model and results file in a location accessible to the user. Any data in the Strand7 model and results file is therefore retrievable and auditable.

Standard report with graphics are available within a much accelerated timeframe.

FUTURE WORK

Eventual iterations to include:

The creation of additional wall types. The creation of double span wall types. Incorporating anchor calculations into the

program, including seismic loads. Incorporating glass make-up calculations

into the program.

FIGURE 3Three variations of a single-span unit.

FIGURE 4A multi-span unit.