Optimization of Bolted Connection in Steel Corbel Attach to RC Column of MRT Viaduct

MRT is one of the backbones of a city’s public transportation system, capable of carrying large crowds. The use of a portal frame in the design of an MRT train station has raised significant concerns about how the portal frame’s load will be supported by the extended structure element known as a corbel. A corbel is a protruding structural element that supports weights like primary beams and girders. Engineers must then decide how to properly bolt the steel corbel structure to the concrete pier segment or columns. Generally, most corbel structure designs were constructed of concrete; however, in this study corbel design was made of steel so that the steel portal frame could rest on the corbel structure, allowing for more usable area on the platform, such as kiosks and other amenities. Optimization of end plate thickness and beam web thickness is carried out. Manual calculations are used in addition to FEA modeling to examine the bolt’s deflection, shear, bearing, tension, slip, and block tearing resistance. When using Eurocode, all three loadings, transverse force, vertical force, and transverse moment, produce values that are 10% lower than the British Standard. As a result, designers can optimize their designs using Eurocode.

EFFECT OF MECHANICAL ANCHORAGE IN HEAT TREATED BEAMS RETROFITTED WITH CFRP

Aim: Locally deformed beams and girders could be temporarily repaired by heat treatment but this practice causes the decrease in the load capacity of the member. Besides, fiber reinforced polymer strips could be used to gain a permanent retrofitting solution for the deformed elements. Method: In this study initially the behavior of heat treated IPE-80 beam strengthened by Carbon Fiber Reinforced Polymer (CFRP) strips bonded with epoxy is observed. This practice causes a significant increase in the load capacity but it is also being observed that epoxy scatters earlier, which does not allow the CFRP to resist much more load. Scaled steel IPE80 beams are selected and they are subjected to three-point bending test. Load-deflection behavior is recorded for each test and conclusions are derived by comparing the results. Conclusion: Preliminary laboratory experiments on shell plates shows that using anchorage by employing bolt has better results compare to those observed by using anchorage made by CFRP fabric only. This study suggests implementation of anchorages through bolts or CFRP fabrics along with epoxy bonding to retrofit the heat treated elements.

Study on Longitudinal Ship Strength Caused by the Placement of Beams and Girders on Upper Deck Side

The location of the beam and the deck girder of the ship can be effect on it is strength especially for the longitudinal strength due to the vertical wave bending moment. The objective of this study is to know the structural response of the ship due to vertical bending moment load on hogging and sagging conditions. The analysis is carried out by using Finite Element Method so-called ANSYSTM. The results shows that the stress occurring on the ship model with deck beam above the deck plate is larger than the ship model with deck beam under the deck plate. When the load with the variated of 0.2 x moment of vertical moment load, there is an increase of stress that occurs both on the deck area about 12% while on the bottom area about 0.98%. This study also conducted a stress comparison by using analysis methods with analytical methods. The results show that by the Stress differences that occur in the structure with the longitudinal deck beam and deck girder above are 14.1% on the deck and 7.1 on the bottom. Whereas in the structure with deck longitudinal deck eam and deck girder under there is a difference of 5.7% on the deck area and 3.5% in the bottom area of the ship. The stress that occur in both models have a difference that is not too far away and still under the permisible stress by the classification society so that both can be applied to the construction of a tanker.

Strain-Based Evaluation of a Steel Through-Girder Railroad Bridge

In the state of New Mexico (USA), passenger rail began in 2008 between Belen and Santa Fe on the Rail Runner, following the acquisition of about 100 miles of existing rail and related infrastructure. Many of the bridges on this route are over 100 years old and contain fatigue prone details. This study focuses on a steel through-girder bridge along this corridor. To accurately evaluate these structures for load carrying capacity and fatigue, an accurate analytical model is required. Accordingly, four models were developed to study the sensitivity of a bridge in New Mexico to floor-system connection fixity and the ballast. A diagnostic load test was also performed to evaluate the accuracy of the finite-element models at locations of maximum moments. Comparisons between the simulated and measured bridge response were made based on strain profiles, peak strains, and Palmgren-Miner’s sums. It was found that the models including the ballast were most accurate. In most cases, the pinned ended models were closer to the measured strains. The floor beams and girders were relatively insensitive to the ballast and end conditions of the floor-system members, whereas the stringers were sensitive to the modeling of the ballast.