Organized by: Department of Civil Engineering

Sponsors:

31st May to 3rd June 2010

Structural TopicThe goal of the project is to design a transformable bridge-like walkway consisting of two half-circles, which can be connected to form both an S-shape and a circle of the walkway.

Both configurations will be tested and assessed. The fabricated model must follow the structural design report submitted.

Non-compliance with the instructions and use of materials not provided by the organizer will lead to disqualification.

Grand Challenge (S-Shape walkway)

An example of timber structural model of the bridge walkway.

Geometric Requirements

Plan view of the S-shape walkway and circle configuration with dimension and clearance requirements.

Plan

Geometric Requirements

Horizontal view of a part of the walkway with dimension and clearance requirements.

Geometric Requirements for Loading

Horizontal view of the end of the walkway with load application and clearance requirements.

Elevation

Material and Tools Materials

Balsa wood slat (15 pieces for each team) with dimension of 1mmx75mmx1000mm

Nylon cord (maximum 3 meters for each team) with diameter of 1 mm.

Adhesive (UHU Hart Balsa cement) Screws (Aluminum, M6)Note: Screws can be used to fix one of the columns

and they are not allowed inside the structure.

Tools Ruler, triangle ruler, protractor, compass, pencils,

cutter knives, sand papers, scissors.Note: Installation of tools in the structure is not allowed.

Structural Requirements The transformable bridge-like walkway has to

be fabricated using wood slat, adhesive and, optionally, nylon rope.

The structure must consist of two half-circles, which can be connected to both an S-shape and a circle of the walkway.

The two parts must be detachable from one another so that both configurations can be tested and assessed.

Structural Requirements

Maximum three columns are allowed to support the walkway.

The type of structure is not specified and not limited but clearance requirement must be satisfied.

Only one of the columns will be rigidly connected to the ground. This column will be fixed to the base by two or four adjustable aluminum brackets. The cross-section of the built-in column must be rectangular over the first 50 mm from the ground.

The bases of the remaining columns are only provided with supports for only horizontal and compressive forces.

Clamped Support

Base construction for clamped column.

Plan

Clamped Support

A typical connection at the bottom of the clamped column.

Simply Supported Base

Base construction for non-clamped columns.

Plan

Other Requirements

The model may be limited to the load-carrying components.

The following parts should be properly designed for load application:The longest free end of the walkway in the S-

shape configurationThe sections in the middle of the longest

span between the columns in both the S-shape and circular-shape configurations.

Load Tests

Both the S-shape and the circle configurations of the model are tested.

Load testing will include both static and impact loads applied in vertical direction:The longest free end of the walkway in the S-

shape configuration In the middle of the longest span between

the columns in both configurations. The static load tests will be carried out

first and those models that pass static tests will be admitted to the impact load tests.

Loading Apparatus

Loading constructions.

Elevation

Load Tests Static load test

The model will be loaded incrementally with three masses of 2.0 kg each.

The final mass is 6.0 kg plus the mass of the load-carrying construction.

The displacement limit is l/100 for the load between two columns and l/50 for the load at the end points of the walkway. Where, l is the distance between the load point and the axis of the next column, measured along the axis of the walkway.

The test will be terminated upon collapse of the model.

Impact load test The final mass of 6.0 kg plus the mass of the load-carrying

construction remains unchanged. Then, the upper mass segment of 2.0 kg is lifted to a height of 80 mm

above its idle position and suddenly released. The test will be considered successful if the model does not collapse

within the first 10 seconds after application of the impact load.

Tentative Schedule for GEM1505C

Time Event

16th or 17th March 2010 Submission of the design report

23rd or 24th March 2010 Fabrication of the S-shape bridge

30th or 31st March 2010 Fabrication of the S-shape bridge

6th or 7th April 2010 Testing of structure

13th or 14th April 2010 Testing of structure

1st – 4th June 2010 6th Inter-University Invitational Civil Engineering Competition

Model appearance The model appearance is focused on the design idea,

innovation, proportion and elegance, realistic layout, and technical elaboration of the construction.

Structural behavior The marks are collected step-by-step during the tests. The lightest model which satisfy all static load tests will be

awarded 25% marks. Load to weight ratios will indicate the rank the larger L/W will get 1% point less consecutively but not less than 13%.

The lightest model to satisfy all impact load tests will be awarded 25% marks. Load to weight ratios will indicate the rank the larger L/W will get 1% point less consecutively but not less than 13%. Those passing the impact load test will receive higher marks than the failed ones.

Assessment

Grand Challenge (S-Shape walkway)

An example of timber structural model of the bridge walkway.