PTCsteel a tool to design steel structure according to Australian standard AS4100 Scientific research topic

Microsoft Word Cover docx FACULTY OF SCIENCE, ENGINEERING AND TECHNOLOGY SCHOOL OF ENGINEERING DEPARTMENT OF CIVIL AND CONSTRUCTION ENGINEERING Master of Engineering (Civil) HES6198 – Research Paper PCTSteel – A tool to design steel structure according to Australian Standard AS4100 Instructor Professor Emad Gad Student Cao Thanh Pham 6657656 SWINBURNE UNIVERSITY OF TECHNOLOGY MELBOURNE, AUSTRALIA Table of Contents 1 Introduction 2 2 Literature review 2 2 1 Design models 2 2 1 1 Design for bendin.

FACULTY OF SCIENCE, ENGINEERING AND TECHNOLOGY

SCHOOL OF ENGINEERING DEPARTMENT OF CIVIL AND CONSTRUCTION ENGINEERING

Master of Engineering (Civil) HES6198 – Research Paper

PCTSteel – A tool to design steel structure according to

Australian Standard AS4100

Instructor: Professor Emad Gad Student: Cao Thanh Pham - 6657656

MELBOURNE, AUSTRALIA

1 Introduction 2

2 Literature review 2

2.1 Design models 2

2.1.1 Design for bending moment 2

2.1.2 Design for axial compression 3

2.1.3 Design for axial tension 4

2.1.4 Design for combined actions of bending and compression and bending and tension 4 2.2 Software available 6

3 Specific design model for non-standard I section 7

4 Developing of PCTSteel tool and its features 10

5 Validation and limitation 13

5.1 Compare with hand computation 13

5.2 PCTSteel charts compare to AISC charts 13

5.3 Limitation of PCTSteel tool 14

6 Conclusion 14

References 15

APPENDIX A 16

APPENDIX B 20

APPENDIX C 21

APPENDIX D 23

1 Introduction

Structural steel is becoming more popular in construction industry because of its usefulness, such as a large bearing capacity and high reliability, light weight, portability during transport and assembly, highly industrialization, and sealed, waterproof Structural steel is suitable for use in structural frame or roof for projects with large span and requires high durability, such as structural frame for industrial factories, roof of stadiums, hangars, and so forth

Design of steel structure can be done manually by hand computation but with this way designer would take much time to perform and repeat the calculation steps until achieving the final results Design of structures by using computer has appeared many years ago, and there are many overall software of structural design, and particular for design of steel structure, such as SAP2000, STAAD.Pro, Midas Gen, Tekla, etc The software help to optimize the time of structural analysis and design The benefits of the software are not small but user is hardly to using them popular because they are commercialized with high cost and have copyright to use

To solve the above problem, a design tool of steel structure is developed on a spreadsheet which will bring the economic and time efficiency for designers or companies by using it This study introduces a compact spreadsheet which is called “PCTSteel” using to design the steel structure according to Australian Standard AS4100 with several design features, for instance designing capacity of bending, compression, tension, and combined actions of bending and compression and bending and tension of many sections At the moment, this design tool covers the designing

of bearing capacity for standard hot rolled sections as UB, UC, WB, WC, PFC, and EA with the grades of 300 and 350, and non-standard I sections

2 Literature review

2.1 Design models

AS4100 sets out minimum requirements for the design, fabrication, erection, and modification

of steelwork in structures in accordance with the limit states design method

This standard is intended to apply also to roadway, railway, and pedestrian bridges However, the requirements given in this standard may not always be sufficient for bridge applications In these circumstances, the specifications of the relevant Authority shall be used

Below is the design procedure of steel structure of bending, tension, compression, and combined actions of bending and tension and bending and compression

2.1.1 Design for bending moment

Section moment capacity Ms:

Ms = fyZe (1) Where, fy = yield stress used in design

Ze = effective section modulus Member moment capacity Mb:

Mb = αmαsMs (2) Where, αm = moment modification factor for bending

αs = slenderness reduction factor

G = shear modulus of elasticity, 80 x 103

J = torsion constant for a cross-section

Iy = second moment about the cross-section minor principal y-axis

Iw = warping constant for a cross-section

le = effective length 2.1.2 Design for axial compression

Section capacity Ns:

Ns = kfAnfy (5) Where, kf = form factor for members subject to axial compression

An = net area of a cross-section Member capacity for buckling Nc:

Nc = αcNs (6) Where, αc = compression member slenderness reduction factor

The nominal section capacity of a tension member shall be taken as the lesser of:

Fracture: Ntf = 0.85ktAnfu (14)

Where, Ag = gross area of a cross-section

An = net area of a cross-section

kt = correction factor for distribution of forces in a tension member

fu = tensile strength used in design

2.1.4 Design for combined actions of bending and compression and bending and

Ø = 0.9, the capacity factor

𝛺 = the ratio, 𝛺 = 1.18 for doubly symmetric I-sections which are compact and kf = 1, and 𝛺 = 1 for the others type

- Nominal section moment capacity reduced by axial force about minor principal y-axis,

Mry:

∗

∅𝑁 (16)

Alternatively, for doubly symmetric I-sections which are compact, Mry is calculated by the following as appropriate:

∅ ≤ 𝑀 (17) Biaxial bending for compression and tension:

- In-plane capacity – elastic analysis:

For compression members:

∗

∅𝑁 (21) For tension members:

∗

∅𝑁 ≤ 𝑀 (24)

* Biaxial bending member moment capacity:

For compression members:

Where, Mcx = the lesser of the nominal in-plane member moment capacity (Mix)

and the nominal out-of-plane member moment capacity (Mox) for bending about the major principal x-axis

For tension members:

Where, Mtx = the lesser of the nominal section moment capacity (Mrx) reduced

axial tension and the nominal out-of-plane member moment capacity (Mox)

2.2 Software available

Currently, there are many software solutions for structural design in the market which included the design of steel structure The popular software are known as SAP2000, Midas Gen, STAAD.Pro, and Tekla Each of software has the significant advantages and disadvantages

In 1970, Professor Edward L Wilson and colleagues have launched the first version of SAP And, now it is developing by the Computers & Structures (CSI), USA The latest version of SAP is SAP2000 v15.0.1 SAP200 analyses the structure based on the finite element method

It has the ability to set many different types of structures, such as steel structures, aluminum structures, and reinforced concrete structures The complicated structures such as cable-stayed bridges, skyscrapers, off shore structures can be designed by this software By integrating many design features in a software, it is sometimes difficult to use for user, or user need to undergo a training course to understand how to use the software Also, cost and copyright issues are a major obstacle for user who wants to access this software

Similar to SAP2000 software, Midas Gen and STAAD.Pro software are two other professional software for structural design, using the finite element method in structural analysis Both software are also designing many different types of structure from complexity to simple Midas Gen was developed by Midas Company in 1989 in North Korea, and used for commercial work

in 1996 Version 6.3.2 is the latest version of Midas Gen STAAD.Pro software was first developed by Research Engineers International Company in Yorba Linda, California, USA Then it was acquired and developed by Bentley Systems Company, USA until now The latest version of STAAD.Pro is STAAD.Pro V8i This software can also design many different types

of structure including concrete, reinforced concrete, steel, and aluminum

Tekla is a software of Tekla Corporation, Finland The remarkable feature of this software compared with others software that are the ability of automatically design and export the structural design drawings Tekla is specialized software use for structural steel design, it is suitable for structural design of industrial factory steel frames and prefabricated steel buildings

In addition, it also adds the features for structural design of reinforced concrete and precast concrete

The above software have outstanding features, depending on the job requirements and habit of using, user will choose a suitable software to use However, these software are commercial

software with high cost So, it is not popular for using of individual user or small construction companies, especially students For instant, a simple design tool of steel structure names “Steel Design” developed by Digital Canal that has the price of $395 So that, developing a computer program of steel structural design above user is helpful

3 Specific design model for non-standard I section

For standard sections, the sections properties can be found from the tables in AISC Volume 1: Open Sections or from the Onesteel Section Category software However, for non-standard section the section properties have to be calculated by hand computation

The calculations of the non-standard I sections properties are presented below

Figure 1 – Non-standard I sections Determine the centroid of a cross-section:

The I section is divided to three small sections which showed in Figure 1

Assume the area of small section 1, 2, 3 are A1, A2, A3, and the coordinates corresponding

of these section centroids to the centroid C of the whole section is (x1, y1), (x2, y2), (x3, y3) Where, C is the centroid of the cross-section, the C coordinates are determined as follow:

𝑋 =∑ (𝑥 𝐴 )

∑ 𝐹 (27)

𝑌 =∑ (𝑦 𝐴 )

∑ 𝐹 (28) Where, Ai = the area of i-th section

xi, yi = the coordinates of i-th section compare to an assumed datum-line of the whole section (xo, yo)

Determine second moment of area of a cross-section, I:

For case 1 of Figure 1:

Determine the radius of gyration, r:

𝐴 (31)

𝐴 (32) Where, Ag is the gross area, Ag = A1 + A2 + A3

Determine the plastic modulus, S:

For case 1 of Figure 1:

Determine the elastic modulus, Z:

𝑍 =𝐼

𝑦 (35)

𝑍 =𝐼

𝑥 (36) Where, x = bf/2, and y = d/2 or y = y1 or y= y3 depend on the cross-section

Warping constant for a cross-section of I sections, Iw:

𝐼 = 𝑑 + + 𝑡 𝑏 𝑡 𝑏

12 𝑡 𝑏 + 𝑡 𝑏 (37) Determine the section compactness and effective section modulus Ze:

Calculate element slenderness values, λe for each plate element:

𝑡

𝑓

250 (38) Determine the ratio for each element, the value of λey reference to table 5.2 of AS4100

The whole section slenderness λs is taken to be equal to the λe value for the largest ratio

𝑍 = 𝑍 𝜆

𝜆 (43) Determine the form factor, kf:

𝑘 =𝐴

𝐴 (44) Where, Ag = Σ(biti), gross area of a gross section

Ae = Σ(beiti) ≤ Ag, the effective cross-sectional area,

𝑏 = 𝜆 𝑡 250

𝑓 ≤ 𝑏 (45) Where, bei is the effective width of the i-th plate element of the section

λeyi is the plate yield slenderness limit, obtained from table 6.2.4 of AS4100

bi is the clear width of a plate element having two plates supporting it longitudinally from crumpling (the web between the flanges), or the outstand of the element supported along one longitudinal edge only (the flange of an open section)

ti and fyi are respectively the thickness and design yield stress of the plate element being considered

4 Developing of PCTSteel tool and its features

PCTSteel is developing based on Australian Standard Steel structures, AS4100

PCTSteel spreadsheet formulas required for the calculation of steel design correspond to Equations 1 to 45 given above There must be as many sets of formulas, arranged in rows in the spreadsheet

PCTSteel tool covers the steel design of bending, tension, compression, and combined actions

of bending and tension and bending and compression

This tool is set to calculate the bearing capacity of sections given in the table below:

- Part 1 is designing of standard sections include UB, UC, WB, WC, PFC

- Part 2 is designing of standard section EA

- Part 3 is designing of non-standard I-section

PCTSteel is divided to be three parts because there are differences of calculation process of the sections above

PCTSteel is using the simple input method which makes it easy and friendly for use Drop down selection menu is integrated for easy use and to get the accurate results of calculation process

Also, the input messages will help user easy to follow the steps of inputting process The input cells are highlight by the dark color to distinguish the input and out cells

Figure 2 – Input section and support input massage

Figure 3 – Drop down selection in the input and summary of results in the output The summary of results is setting at the first look of output section, which is for quick check of satisfied or unsatisfied of a chosen section User just compares the result from input data and summary of results in the output data to get the most satisfying section This could be known

as a solution for the economic problem, which is hard and spends a lot of time to do it if manually calculation by hand

The top buttons will let user to know where they are in the PCTSteel spreadsheet These buttons also use to jump up from this sheet to another sheet For instant, the Figure 4 below shows that, user is staying in the calculating of bending of standard sections by look buttons by the red highlight If user clicks one of any upon buttons it will move to calculate for the other tasks like tension of standard sections or equal angle sections or non-standard I-section

Figure 4 – Support buttons for switching between the calculation tasks

The output data is showing the results of calculation and the correlative formulas This output type will help users easy to follow step by step how the results coming out and can recheck manually by hand computation

Figure 5 – The illustrative output data Beside the features above, PCTSteel tool is also designed to draw the charts of bending and compression capacity of any sections including equal angle and non-standard I-section The charts are clearly shown the member moment capacity or the compression moment capacity of the section which is using of design and the design moment load or design compression load for easer comparison

Figure 6 – The member moment capacities and the design moments about X and Y-axis of

610UB125 grade 300

5 Validation and limitation

5.1 Compare with hand computation

Using PCTSteel, user does not take much time to perform the repetitive calculations many times

to be met the suitable section which compares to calculation by hand User simply enters the input data and selects the appropriate section for completing the computational task

For hand computation, it takes a lot of pages of paper for calculating phase The errors and mistakes could be occurred during calculating, this leads to get inaccurate results in the final results

PCTSteel tool only provides to user a single page of calculation which easy to check and review

It will take a few minutes of user to finish the calculation and get the results The calculation process can also print out for approve design or checker

5.2 PCTSteel charts compare to AISC charts

Basically, the charts of design member moment capacity ØMb and design member capacity in axial compression ØNc present by PCTSteel tool are the same with the charts provided by AISC However, the charts from PCTSteel are easier to follow than AISC’s charts because the PCTSteel’s charts are showing only one currently section

The comparison of PCTSteel’s chart and AISC’s charts are shown in the Appendix A