Abstract
In this paper, through operational modal analysis and ambient vibration tests, the dynamic characteristics of a multi-span simply-supported reinforced concrete highway bridge deck was determined and the results were used to assess the quality of construction of the individual spans. Supporting finite element (FE) models were created and analyzed according to the design drawings. After carrying out the dynamic tests and extracting the modal properties of the deck, the quality of construction was relatively assessed by comparing the results obtained from all the tests from the individual spans and the FE results. A comparison of the test results among the different spans showed a maximum difference value of around 9.3 percent between the superstructure's natural frequencies. These minor differences besides the obtained values of modal damping ratios, in which the differences were not more than 5 percent, can be resulted from suitable performance, health, and acceptable construction quality of the bridge.
Key Words
acceleration sensor; bridge; modal analysis; structural health monitoring
Address
Reza Akbari: Road Maintenance Department, Road Maintenance and Transportation Organization, Tehran, Iran
Saeed Maadani: Department of Engineering, Takestan Branch, Islamic Azad University, Takestan, Iran
Shahrokh Maalek: School of Civil Engineering, University of Tehran, Tehran, Iran
Abstract
The safety of bridges are critical in our transportation infrastructure. Bridge design and analysis require complex structural analysis procedures to ensure their safety and stability. One common method is to calculate the maximum moment in the girders to determine the appropriate bridge section. Girder distribution factors (GDFs) provide a simpler approach for performing this analysis. A GDF is a ratio between the response of a single girder and the total response of all girders in the bridge. This paper explores the significance of GDFs in bridge analysis and design, including their importance in the evaluation of existing bridges. We utilized Bridge Weigh-in-motion (B-WIM) measurements of five simple supported girder bridge in Indonesia to develop a simple GDF provisions for the Indonesia's bridge design code. The B-WIM measurements enable us to know each girder strain as a response due to vehicle loading as the vehicle passes the bridge. The calculated GDF obtained from the B-WIM measurements were compared with the code-specified GDF and the American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) bridge design specification. Our study found that the code specified GDF was adequate or conservative compared to the GDF obtained from the B-WIM measurements. The proposed GDF equation correlates well with the AASHTO LRFD bridge design specification. Developing appropriate provisions for GDFs in Indonesian bridge design codes can provides a practical solution for designing girder bridges in Indonesia, ensuring safety while allowing for easier calculations and assessments based on B-WIM measurements.
Key Words
B-WIM; bridge analysis; bridge design; girder bridge; girder distribution factor
Address
Widi Nugraha, Indra Djati Sidi,
Made Suarjana and Ediansjah Zulkifli: Departement of Civil Engineering, Faculty of Civil and Environmental Engineering, Institut Teknologi Bandung, Jl Ganesha No 10 Bandung 40132, Indonesia
Winarputro Adi Riyono: Directorate of Road and Bridge Engineering Development, Directorate General of Highway,
Ministry of Public Works and Housing, Indonesia Jl AH Nasution 264 Bandung, Republic of Indonesia
Abstract
Internal and external corrosion are common in pressure pipes used in a variety of industries, often resulting in defects that compromise their integrity. This economically and industrially significant problem calls for both preventive and curative technical solutions to guarantee the reliability of these structures. With this in mind, our study focuses on the influence of composite and metallic patch repairs on the limit loads of pipes, particularly elbows, the critical component of piping systems. To this end, we used the nonlinear extended finite element method (X-FEM) to study elbows, a priori corroded on the internal surface of the extrados section, then repaired with composite and metallic patches. In addition, the effect of the geometry of composite materials and metal patches was examined, in particular the effect of their thickness and material on the increase in limit loads of repaired structures. The results obtained provide information on the effectiveness and optimization of patch repair of corroded elbows, with the aim of increasing their service life.
Address
Chaaben Arroussi and Mohammed Hadj Meliani: LPTPM, Departement of Mechanical Engineering, Faculty of Technology,
Hassiba BenBouali University of Chlef, P.O. Box. 151 Hay Salem, 02000 Chlef, Algeria
Azzedine Belalia: LEM, Faculty of Technology, Hassiba Benbouali University of Chlef, Esalem City, 02000, Chlef, Algeria
Abstract
Indonesia has had seismic codes for earthquake-resistant structures designs since 1970 and has been updated five times to the latest in 2019. In updating the Indonesian seismic codes, seismic hazard maps for design also update, and there are changes to the Peak Ground Acceleration (PGA). Indonesian seismic design uses the concept of building performance levels consisting of Immediate occupancy (IO), Life Safety (LS), and Collapse Prevention (CP). Related to this performance level, cases still found that buildings were damaged more than their performance targets after the earthquake. Based on the above issues, this study aims to analyze the performance of base isolation design on existing target buildings and analyze the seismic fragility for a case study in Indonesia. The target building is a prototype design 8-story medium-rise residential building using the reinforced concrete moment frame structure. Seismic fragility analysis uses Incremental Dynamic Analysis (IDA) with Nonlinear Time History Analysis (NLTHA) and eleven selected ground motions based on soil classification, magnitude, fault distance, and earthquake source mechanism. The comparison result of IDA shows a trend of significant performance improvement, with the same performance level target and risk category, the base isolation structure can be used at 1.46-3.20 times higher PGA than the fixed base structure. Then the fragility analysis results show that the fixed base structure has a safety margin of 30% and a base isolation structure of 62.5% from the PGA design. This result is useful for assessing existing buildings or considering a new building's performance.
Address
Faiz Sulthan: Implementation Unit for Building Materials and Structures, Directorate General of Human Settlements, Ministry of Public Works and Housing, Panyawungan, Cileunyi, Bandung, West Java 40622, Indonesia
Matsutaro Seki: Building Research Institute 1 Tatehara, Tsukuba, Ibaraki 305-0802, Japan
Abstract
Magnetic flux sensors are commonly used in monitoring the cable force, but the application of the sensors in large diameter non-closed Galfan cables, as those adopted in Yueqing Gymnasium which is located in Yueqing City, Zhejiang Province, China and is the largest span hybrid space structure in the world, is seldom done in engineering. Based on the construction of Yueqing Gymnasium, this paper studies the cable tension monitoring using the magnetic flux method across two stages, namely, the pre-calibration stage before the cable leaves the rigging factory and the field tension formation stage of the cable system. In the pre-calibration stage in the cable factory, a series of 1:1 full-scale comparative tests were carried out to study the feasibility and relability of this kind of monitoring method, and the influence on the monitoring results of charging and discharging voltage, sensor location, cable diameter and fitting method were also studied. Some meaningful conclusions were obtained. On this basis, the real-time cable tension monitoring system of the structure based on the magnetic flux method is established. During the construction process, the monitoring results of the cables are in good agreement with the data of the on-site pressure gauge. The work of this paper will provide a useful reference for cable force monitoring in the construction process of long-span spatial structures.
Key Words
cable tension monitoring; cable-truss string-support system; Galfan cable; long-span spatial structures; magnetic flux sensor
Address
Yuxin Zhang and Xiang Tian: School of Civil Engineering, Shanghai Normal University, Shanghai 201418, China
Juwei Xia: Space Structures Research Center, Zhejiang University, Hangzhou 310027, China
Hexin Zhang: School of Computing, Engineering and the Built Environment, Edinburgh Napier University, Edinburgh EH10 5DT, Scotland, UK
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