Problem 1 Influence Lines 13 Marks A Truss Bridge Is Needed To Span A Creek In A Local Park A Concrete Deck Of Width 1 (53.63 KiB) Viewed 59 times
Problem 1: Influence lines (13 marks) A truss bridge is needed to span a creek in a local park. A concrete deck of width 3 m is supported by two identical trusses on two sides. The dimensions and a sectional view of a truss is shown below. Loads travel in top chord. A) Draw influence line diagrams for member forces in members CD anlKD of the truss. K H G 1.5 m B -2 m +-2 m D ---- 2 m 1-2 m -2 m-42 m-4 B) The local council has identified two load case scenarios for design: Load Case 1: An equipment delivery vehicle with the wheel loads as shown in the figure below. Load Case 2: A 3.5 kPa uniformly distributed moving load (UDL) with a length of 4 m.
B) The local council has identified two load case scenarios for design: Load Case 1: An equipment delivery vehicle with the wheel loads as shown in the figure below. Load Case 2: A 3.5 kPa uniformly distributed moving load (UDL) with a length of 4 m. 40 KN 20 KN 25 KN Load case 1 B. 4 m 2 m Note that the vehicle can travel in either direction along the centre of the deck. Accordingly, the load will be carried equally by the two trusses. Assume load factor of 1.5 for both moving loads (Load Case 1 and 2) and ignore the self-weight of the truss and deck Using influence line diagrams, calculate the following: i. Determine the maximum ultimate member force in truss member CD, Fco under the load case 1. (You can use either trial and error or slope analysis method).
ii. Determine the maximum ultimate member force in truss member CD, Fco under the load case 2. Compare the effect of these two different load cases on member CD and suggest the design force to be considered for the design of member CD. iii.
Join a community of subject matter experts. Register for FREE to view solutions, replies, and use search function. Request answer by replying!