Muhammad Ibnu Syamsi

This study investigates the application of the Damage Locating Vector (DLV) method for detecting and localizing damage in two-dimensional truss structures using modal parameters obtained from two sources: ideal data from Modal Analysis in SAP2000 and simulated experimental data from Impact Tests processed via the Frequency Domain Decomposition (FDD) method. Numerical simulations were performed on a 2D truss model under various single and multiple damage scenarios, represented by reductions in member cross-sectional areas. Damage localization was evaluated using the Weighted Stress Index (WSI), where values below one indicated potential damage. The results show that the DLV method effectively identified damage when using modal data from SAP2000, even for minor damage levels of 10%, while lower accuracy was observed when using data derived from simulated Impact Tests. Nevertheless, damaged elements generally exhibited lower WSI values than undamaged ones, confirming the method’s sensitivity and robustness under different data conditions. This research contributes to the advancement of vibration-based damage detection by validating the DLV method’s applicability to 2D truss systems. The findings provide practical implications for nondestructive monitoring and preventive maintenance of civil infrastructure, supporting safer, more reliable, and sustainable structural systems.

Bridges are essential components of transportation networks and play a crucial role in the operation of our infrastructures. As a result, inspecting, maintainin Bridges are essential components of transportation networks and play a crucial role in the operation of our infrastructures. As a result, inspecting, maintainin

A bridge is an essential component of transportation networks and plays a crucial role in the operation of infrastructure, so maintaining this structure to guarantee the regular operation of bridges in a healthy condition is needed. The establishment of a bridge model numerically is a critical step of the bridge evaluation because many cases of the bridge test can be done numerically. The generated results can then be verified and adjusted with the real or full-scale test. This research aims to establish a numerical model of a cable-stayed bridge and perform numerical bridge tests and earthquake simulations. The targeted bridge is located in Taiwan, and it consists of four spans with three pylons. Static load tests are performed using a truck load set applied at each mid-span. Bridge displacement due to the truckloads is the primary concern of the static load test. Besides, dynamic bridge simulation under earthquake excitation is also simulated. On 18 September 2022, a destructive earthquake of moment magnitude (Mw) 7.1 occurred in Taitung County, southeastern Taiwan. Some infrastructures like bridges and buildings were damaged and even collapsed due to this earthquake. The bridge is simulated using the earthquake history record of the earthquake. The bridge's dynamical system properties are first outputted to see the bridge's natural frequencies and mode shapes. Displacement and stress history responses due to the earthquake excitation at some critical points are also evaluated. The simulation results can be a reference for real bridge testing.

The development of vibration-based tension determination has increased in recent years. The effective vibration length concept is one of the most robust methods in dealing with various end-rotational support stiffness. Recently, a two-mode combination approach by compelling multiple frequencies and effective lengths has been developed to replace the bending rigidity from the cable relationship so the tension can be solved explicitly. This paper aims to compare the tension prediction using the effective length concept with two existing methods: linear regression and the two-mode combination. Three cases of cable support: hinged-hinged (Case 1), hinged-fixed (Case 2), and fixed-fixed (Case 3), are studied through numerical simulation. The cable is vibrated under random excitation, and its dynamical properties are extracted through the SSI method. Equivalent frequencies and equivalent-effective lengths are computed to perform the two-mode approach. The study shows that linear regression produces more minor errors than the two-mode combination method, either for Cases 1, 2, or 3. The theoretical results are presented to figure out the cause of errors. However, linear regression and the two-mode method both produce promising results in calculating the cable tension in these three cases. Similar results are also shown in the study using experimental laboratory test data.

The determination of existing cable forces is essential for evaluating the performance of bridges. The vibration technique is preferred among available practical methods because it is simple, fast, and economical. To apply this method, many researchers introduced analytical and empirical formulas considering bending rigidity, cable length, and boundary conditions. Nevertheless, most existing procedures to determine cable forces are for single cables, which are unsuitable for cable networks. To measure the cable forces of the cable networks, engineers should remove any cross-ties before conducting field tests. However, the removal of cross-ties separates the cable network into two independent cables, which does not reflect the actual behavior of the cable network. Hence, to save time and improve accuracy, this paper introduces a method to directly identify the cable tensions of a two-cable network without removing any cross-ties. This technique can precisely estimate the cable forces of the two-bending cable networks with arbitrary boundary conditions with an error of less than 1.0 percent.