Bridge Dimensions and design criteria
To avoid illegal copy from previous years’ projects, please use the exact project parameters as follows. Otherwise, 0 mark will be applied.
·The truss structure has a span of 30m and height of 3m. There are altogether 7 trusses included in the project. Each tutorial class will be assigned one of them as the design project.
·Design Loads include dead load due to self-weight of decking, truss structure, decorations and so on,
G=48kN(design value, no loading factor required here) plus live load due to moving vehicle
P=420kN(design value, no loading factor required here). Each small group should calculate truss member forces due to the combination of dead load and live load at one joint. (for example, group 1 will analyse dead load+live load acting at B point,; group 2 will analyse dead load+live load acting at C point….)
·Truss member will be chosen from steel square hollow section as in attached tables. Design strengths should be taken as
450MPafor tension and
300MPafor compression (approximately taking into account of compressive buckling). You do not have to consider safety factor in this project.
Mechanics of Materials Project 1 Truss Bridge Design (10% of course assessment) Introduction Bridges are an important part of roads and railways because they make it possible to cross rivers and deep valleys. A bridge has to support its own weight as well as the load applied by the vehicles that cross it. Since ancient times, engineers have developed many types of bridges to withstand all forces of nature, namely, the beam bridge, the truss bridge, the arch bridge, the cable stayed bridge and suspension bridge. Due to its construction efficiency, truss structure has been the most common structural type in bridge engineering. The action of an external force on a structure produces internal forces within a structure. The most common types of internal force in a truss structure are Tension and Compression. Associated with each of these force states are related internal stresses and strains which you are going to learn intensively through this course. As the basic design principle of engineering, all internal stresses should be no greater than the allowable stress of the material. Truss Bridge Project This project is designed to provide students with an opportunity to put their theoretical knowledge to engineering practise. Students in one tutorial class will work together to design a 30m span steel truss bridge under required loads. In this project, you are required to work in a group of three-four to design a steel truss bridge. You can select your own Group; however you must all be in the same practical class. Rules · Each tutorial class will be assigned one truss type and the whole class will work together to calculate its member forces subjected to required loads. Each small group will work on one combined loading case through hand calculation. · Each small group need to calculate the truss member forces for all loading cases through software. · Based on the maximum member forces among all loading cases, each group will design the truss members and write up a design report. Bridge Dimensions and design criteria To avoid illegal copy from previous years’ projects, please use the exact project parameters as follows. Otherwise, 0 mark will be applied. · The truss structure has a span of 30m and height of 3m. There are altogether 7 trusses included in the project. Each tutorial class will be assigned one of them as the design project. · Design Loads include dead load due to self-weight of decking, truss structure, decorations and so on, G=48kN (design value, no loading factor required here) plus live load due to moving vehicle P=420kN (design value, no loading factor required here). Each small group should calculate truss member forces due to the combination of dead load and live load at one joint. (for example, group 1 will analyse dead load+live load acting at B point,; group 2 will analyse dead load+live load acting at C point….) · Truss member will be chosen from steel square hollow section as in attached tables. Design strengths should be taken as 450MPa for tension and 300MPa for compression (approximately taking into account of compressive buckling). You do not have to consider safety factor in this project. Detailed schedule Semester Week Tutorial Activity Before the next session 2 Truss analysis To complete in week 4 3 Truss member deign and final report writing Report due by 9 am Monday in week6 Group marks Assessment for group work will be based on the following criteria (also see the feedback form at the end of this project description): Truss analysis (5marks) 1. Hand calculations (3marks) Each student is required to find member forces for 3 different truss members. For example, if there are 3 students in one group, the final report should include 3*3=9 member forces by hand calculation. 2. Software check (2mark). The mark will be assigned based on the accuracy of calculation. A recommended software is SPACE GASS with free student version available at the link of www.spacegass.com or in computers pools at F building or P building-Mawson Lakes campus. The Space Gass truss model is available at learnonline course site. But you have to change the loading input according to your project. Comparison between hand calculations and software results should be compared in a summary table. Report (5 marks) This will be judged from member design, general quality of presentation, drawings, and result discussion. All reports should be submitted through course online system. Each group should submit the two reports only once: (1) Truss analysis report (You can do it by hand, but need scan your writing report in e-file) (2) Final report together with peer assessment (In type) (3) Peer assessment will be done through SPARK Individual mark and peer Assessment Peer assessment is required for each group member. All students in one group should appear in each practical class and report to the tutor the project progress and the job has been done by each person. Absence should get permission from all other group members if with special reasons. Those who contribute less than average will get lower marks or 0 mark accordingly. Those who contribute more than average will get a higher mark with up to 10% increase based on the group mark. Peer assessment will be submitted through Spark Plus. Submission and Late submission All reports should be submitted through course online system. Email to tutor or lecturer will not be accepted. Based on NBE policy, late assignments that do not have approved extensions will incur the following penalties: (1). 5% of the maximum available for the assignment per day will be deducted off the final mark awarded to an assignment. For example, if you score 75% (e.g. 15/20 marks) for your assignment, but it is two days late you will lose 10% and thus score 65% (e.g. 13/20 marks) respectively for your assignment. A total of 5% will be deducted for every 24 hr period – regardless if the assignment is 30 minutes late, or 24hrs late. (2). Late assignments will not be accepted more than 5 working days after an assignment deadline. School of Advanced Natural and Built Environment Assessment feedback CIVE 2005– Mechanics of Materials Truss Bridge design project – (10%) Student Names: Key components of this assignment Mark Comment by marker Truss analysis /5 · Hand calculation/3 · Software check /1.5 · Comparison between hand calculation and software results/0.5 Bridge design /3 · Critical member forces/1.5 · Member design/1.5 · General format and presentation /2 · Introduction, conclusion and/or discussion/1report writing style · clarity of expression · correct grammar, spelling and punctuation Summary comment The Graduate qualities being assessed by this assignment are indicated by an X: X GQ1: operate effectively with and upon a body of knowledge GQ5: are committed to ethical action and social responsibility GQ2: are prepared for lifelong learning X GQ6: communicate effectively X GQ3: are effective problem solvers GQ7: demonstrate an international perspective X GQ4:can work both autonomously and collaboratively Assignment grade/mark: Appendix of Truss types Truss 1 Truss 2 Truss 3 Truss 4 Truss 5 Truss 6 Truss 7 University of South Australia Steps for truss design in project 1: 1. You should have finished truss analysis through hand calculation and SPACE GASS. All member forces have been found. 1. You need consider nearly 10 loading cases in Space Gass analysis with vehicle loadings at different points. That means that there are nearly 10 force values for member AB, 10 values for member BC; 10 values for member CD…. 1. From the nearly 10 values for AB, you can select the critical one (maximum) as the design force, Then you can find the required cross section area for the member: Required area=design member force/allowable stress. Then you can select a suitable section from the cold formed steel section table which is available on course online system. That is the design for member AB. You should repeat the same procedure for all other members BC, CD, DE… 1. In the final report, you should include cover sheet (group number, truss type; group member ), a brief introduction including a picture of your truss, a summary of hand calculations; a summary table of member forces in nearly 10 loading cases; design table (how to select the cross section for each member); total weight of your design truss and a brief conclusion. You do not have to include all detailed calculations, instead you can give one or two examples to show your design procedure and show the main results in the summary tables mentioned above. Remember to note tension or compression in your member forces. Tubecolor DCT Cover COLD FORMED - SRUCTURAL HOLLOW SECTIONS & PROFILES 24ONESTEEL MARKET MILLSNovember 2004 TA B LE 3.1(a) D IM E N S IO N S A N D P R O P E R T IE S T U B E L IN E ®® ®®® S Q U A R E H O L L O W S E C T IO N S G R A D E C 3 5 0 L 0 (A S 1 1 6 3 ) D IM E N S IO N A N D R A T IO S P R O P E R T IE S P R O P E R T IE S F O R D E S IG N TO A S 4100 D esig n atio n M ass E xtern al G ro ss To rsio n To rsio n F o rm p er m S u rface A rea b -2 t S ectio n A b o u t x-, y- an d n -axis C o n stan t M o d u lu s F acto r A b o u t x- an d y-axis t A rea d b t p er m p er t A g Ix Z x Z n S x rx J C k f λλ λλλ e C o m p actn ess (3) Z e m m m m m m kg /m m 2/m m 2/t m m 2 10 6m m 4 10 3m m 3 10 3m m 3 10 3m m 3 m m 10 6m m 4 10 3m m 3 (C ,N ,S ) 10 3m m 3 N O T E S : 1. T his table is calculated in accordance w ith A S 4100 using design yield stress fy = 350 M P a and design tensile strength fu = 430 M P a as per A S 4100 table 2.1 for A S 1163 grade C 350L0. 2. G rade C 350L0 is cold form ed and therefore is allocated the C F residual stresses classification in A S