On the Experimental Stress Analysis of a Composite Box Girder Bridge

Experimental researches on composite box girders have been carried out on several bridges and test models and their structural behaviors are gradually becoming clear. The results of the measured stresses obtained at the Yamasu Bridge built in Kyoto in 1955 and the considerations of these results are described in this report. There is good agreement between the theoretical predictions and the actual behavior

Database for structural steel experiments under a distributed collaboration environment

Due to the high requirements of civil infrastructures against the earthquake in Japan, a great number of research organizations have been conducting the structural steel experiments, in particular the seismic tests such as the cyclic loading test and the pseudo-dynamic test, for many years to determine the seismic performances of steel structures. However, the original test data gained by most research organizations are not well stored in an appropriate manner for distribution and possible usage of others. Although a Numerical Database of Steel Structures (NDSS) was developed some years ago to preserve and share experimental data of the ultimate strength tests acquired at Nagoya University, it was not easy to access this database from other computer platform due to the lack of the support of proper communication media. With the rapid development of information networks and their browsers, structural engineers and researchers are able to exchange various types of test data through Internet. This paper presents the development of a distributed collaborative database system for structural steel experiments. The database is made available on the World-Wide Web, and the Java language enables the interactive retrieval efficiently. The applications of the developed database system for the retrieval of experimental data and seismic numerical analysis are validated in the form of examples.<br /

STATIC AND DYNAMIC BEHAVIOR OF LENS-TYPE SHEAR PANEL DAMPERS FOR HIGHWAY BRIDGE BEARING

This paper describes a lens-type shear panel damper newly developed for highway bridge bearing. It has the form of concave lens shape made of low-yield steel LY 100. Both low yield strength and high ductility are the major requirements for damping devices. Response by static and dynamic shear tests results in rectangular sharpe of load-displacement hysteretic loops with high quality damping. Failure at the ultimate state highly depends on the cumulative deformation capacity of panel. Damage and life cycles can be estimated by Miner's rule. The analytical estimates agree well with the test findings. Large deformation of steel with high speed strain rate generates a lot of heat leading to high temperature of 300～400 ℃ on swface. Earthquake energy is converted to both strain and heate nergies wof hich results in large energy dissipation

Design and Experimental Performance Evaluation of Lens-type Shear Panel Dampers for Highway Bridge Bearings

This paper describes lins-type shear damper newly developed for highway bridge bearing. It utilizes low-yield steel LY100 and concave lins-shape panels. Both properties provide low strength and high ductility which are major requirements for damping devices, then contributes to high energy dissipation against seismic motion. Large deformation due to high speed strain velocity causes steel lens plate heating up to 400-500 centigrade in a moment. Earthquake energy is converted both to strain energy and heat energy. Cumulative deformation capacity of lens identity determines ultimate state of failures associated with strength and life time, dependent on time history of level-2 desibn earthquake(EQ). Fracture is roughly estimated by Miners rule esing damage index method. Prediction matches well with testing results. As case study with dampers, dynamic analysis on the existing continuous bridges has been conducted with some design parameters. The base shear acceleration due to livel-2 earthquake reduces down to 0.45g～0.5g from 0.8g of lead rubber bearing system. For planning of bridge system with dampers, 1-DOF model is simply useful to roughly know the base shear with dampers at the initial stage of planning onil when dead load is known. Design methods and experimental performance evaliation results are reported