This Project encompassed two structures: tunnel and bridge, located at a busy junction and difficult topography in Damascus downtown. The tunnel had variable width from 8 to 11, and was covered by filling material in a thicknesses varied from 0 to 3.1 m. The bridge had 4 continuous spans cast in-situ. See below for further pictures.
My Role in the Project (in Detail):
1) I analyzed and designed the tunnel using 3D shell element model. I used the tension only springs to simulate the soil-structure interaction (boundary conditions), fig. (65, 66, 67 and 68).
2) I proposed 3 different configurations for the bridge, fig (69). The architectural golden ratio was employed for dimension’s proportion in the alternatives. The client adopted the solid slab alternative, fig (70)
3) I performed the static and modal analysis of the bridge according to these different methods:
· Space grillages utilizing STAAD PRO., see fig (71). I paid special attention to represent the geometry, property and elevation of the grillage elements to take into account the exact interaction between the internal forces (especially the combination between bending and torsion moments), the results were captured for each 1m strip in terms of shear and moment diagrams.
· 3D Shell element model using STAAD PRO, see fig (72). I used this model to verify the first model, check the worst scenario of moving loads, simulate the print of the pier on the superstructure (by means of master/slaves nodes), and to help find the reinforcement layouts, cuts and anchorage lengths in the superstructure.
· Solid volumetric model utilizing ANSYS software, see fig. (73). I created this model to solve an argument with the superintendent. This model verified the stress distribution within the slab, stress localizations and stress intensities in some specific details. Also, the results were: the plastic deformations, the failure criteria and the failure modes. In addition to that the model helped to determine the safety margins that were included in the design.
· Eigenvalue (modal) analysis was carried out for the bridge, followed by response spectrum analysis. I performed these two analyses to get the elastic response of the bridge due to earthquake, and to design some sections in the bridge according to the results.
· Static linear dynamic analysis (elasto-plastic pushover analysis), I used this analysis to identify the behavior and the level of performance of the bridge. In another hand, to confirm the desired collapse mechanism.
· A CSI short program (PCACOL) was used to find the interaction diagram for the piers.
4) I drew the concept and some details of the structures using AutoCad, and the final format of the drawings were performed by the drafters, and I supervised this stage. The drawing standards and details were mainly according to (ACI 315-99) with some modifications to adapt the local experience, figures (74 and 75).
5) I audited the quantity surveying of the project, and I participated in finding a solution for maintaining the traffic flow during construction. I produced time bar charts that indicate the construction sequence, anticipated delays and night time shafts.
6) I visited the construction site to check the reinforcement position, and it can be seen from fig. (76) some photos that were taken during my visits of the construction site.
All formulas that I used to design the structures were according to AASHTO LRFD, and Caltrans.
