TRANSIENT TESTING OF SEISMIC RECORDING APPARATUS

Geophysics ◽  
1940 ◽  
Vol 5 (4) ◽  
pp. 337-347 ◽  
Author(s):  
Harold Washburn ◽  
Raymond Olesen
Keyword(s):  
Shaking Table ◽  
High Fidelity ◽  
Mechanical Motion ◽  
Recording Equipment ◽  
Recording Apparatus ◽  
Response Characteristics ◽  
Seismic Recording ◽  
Actual Field ◽  
Test Table

A transient generator and shaking table suitable for testing response characteristics of seismometers and associated amplifier and recording equipment is described. From variable‐area sound‐on‐film records representing idealized transients or actual field seismograph recordings, the generator and shaking table provide a high‐fidelity conversion to mechanical motion of the test table. The special experimental truck used in obtaining test records is also described briefly.

scholarly journals New Frontiers of Seismic Surveying in Antarctica: The Mapping of A Thin Layer at the Base of Ice Stream B (Abstract)

1986 ◽  
Vol 8 ◽  
pp. 202-202
Author(s):  
Donald D. Blankenship
Keyword(s):  
Thin Layer ◽  
Seismic Reflection ◽  
Dynamic Range ◽  
Basal Layer ◽  
Recording Equipment ◽  
Power Requirement ◽  
Large Bandwidth ◽  
Ice Stream ◽  
Seismic Recording ◽  
Ice Stream B

The recent availability of high resolution (greater than 250 Hz) seismic recording equipment in the Antarctic field environment has allowed the acoustical mapping of a previously unobserved subglacial phenomenon. This phenomenon is a thin (less than 10 m), yet continuous, layer at the base of Ice Stream B in West Antarctica. Discovery of this layer came during the 1983–84 austral summer in a seismic reflection survey that covered approximately 10 km2 near the Upstream B field camp (83°31’S, 138°05’W). Although analysis of the seismic data is at a preliminary stage, there is the possibility that this feature could be a basal “lubricating” layer; some sort of lubrication is of course necessary to explain the very large horizontal velocities of these ice streams.During the seismic reflection survey on Ice Stream B, a new digital seismic recording system, developed by the Geophysical and Polar Research Center, was used for the first time under field conditions. Resolution of such a thin layer was possible only because of the very large bandwidth (0–600 Hz) and dynamic range (84 dB) of this device; this bandwidth is about twice that possessed by commercially available seismic recorders. In addition, a new level of portability (i.e. a weight of 40 kg and a power requirement of 90 watts), which should make this device usable in virtually any Antarctic field situation, has been achieved by the application of advanced recording technologies. The portability of this digital seismic recorder, when combined with its large bandwidth and dynamic range, should result in the resolution of a whole new class of intra- and subglacial phenomena, of which the thin basal layer of Ice Stream B is the first example.

scholarly journals Dynamic Response Characteristics of Aeolian Sediment along Sichuan-Tibet Railway

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Kan Han ◽  
Chunxiao Xue
Keyword(s):  
Dynamic Response ◽  
Ground Motion ◽  
Shaking Table Test ◽  
Soil Layer ◽  
Time History ◽  
Surface Displacement ◽  
Shaking Table ◽  
Aeolian Sand ◽  
Response Characteristics ◽  
Dynamic Response Characteristics

In order to reduce the damage of liquefaction of aeolian sand along the Sichuan-Tibet railway, the dynamic response characteristics of saturated aeolian sand in the study area were discussed by using shaking table test. The results show that the macroscopic characteristics of saturated aeolian sand in the study area are subsidence, water flow and fracture. The displacement time history shows that the surface displacement increases with increasing the input ground motion acceleration. When the acceleration is small (0.1g), the vibration in the soil layer has an obvious tendency to enlarge continuously from bottom to top. With the increase of the acceleration (0.2g), the amplification trend basically disappeared. When the acceleration increases to 0.3g, the ground motion increases first and then decreases.

scholarly journals Experimental Approach for the Failure Mode of Small Laminated Rubber Bearings for Seismic Isolation of Nuclear Components

2021 ◽  
Vol 12 (1) ◽  
pp. 125
Author(s):  
Sang-Jin Ma ◽  
Tae-Myung Shin ◽  
Ju-Seung Ryu ◽  
Jin-Hyeong Lee ◽  
Gyeong-Hoi Koo
Keyword(s):  
Seismic Isolation ◽  
Response Spectrum ◽  
Shaking Table ◽  
Intensity Level ◽  
Shaking Table Tests ◽  
Response Characteristics ◽  
Water Jet Cutting ◽  
Total Failure ◽  
Rubber Bearings ◽  
Partial Damage

Response characteristics of small-sized laminated rubber bearings (LRBs) with partial damage and total failure were investigated. For nuclear component seismic isolation, ultimate response characteristics are mainly reviewed using a beyond design basis earthquake (BDBE). Static tests, 3D shaking table tests, and verification analyses were performed using optional LRB design prototypes. During the static test, the hysteresis curve behavior from buckling to potential damage was observed by applying excessive shear deformation. The damaged rubber surface of the laminated section inside the LRB was checked through water jet cutting. A stress review by response spectrum analysis was performed to simulate the dynamic tests and predict seismic inputs’ intensity level that triggers LRB damage. Shaking table tests were executed to determine seismic response characteristics with partial damage and to confirm the stability of the superstructure when the supporting LRBs completely fail. Shear buckling in LRBs by high levels of BDBE may be quickly initiated via partial damage or total failure by the addition of torsional or rotational behavior caused by a change in the dynamic characteristics. Furthermore, the maximum seismic displacement can be limited within the range of the design interface due to the successive slip behavior, even during total LRB failure.

Seismic Testing of a Long-Span Concrete Filled Steel Tubular Arch Bridge

2010 ◽  
Vol 456 ◽  
pp. 89-102 ◽  
Author(s):  
Wei Ming Yan ◽  
Yong Li ◽  
Yan Jiang Chen
Keyword(s):  
Dynamic Performance ◽  
Internal Force ◽  
Shaking Table ◽  
Structural System ◽  
Arch Bridge ◽  
Seismic Testing ◽  
Response Characteristics ◽  
Long Span ◽  
Bridge Model ◽  
Cfst Arch Bridge

Long-span bridges are always a multi-support structural system, and seismic ground motion can vary significantly over distances comparable to the length of such kind of bridges, so it’s difficult to carry out shaking table tests because of the restriction of the dimension and amount of shaking tables. This paper discusses the multiple sub-table cordwood system is used to conduct a study on the seismic testing of a three-span irregular Concrete filled steel tubular (CFST) arch bridge with the objective of investigating the dynamic performance of the bridge under spatial earthquake motions. The development and testing of the bridge model and selected experimental results are discussed then. The seismic response and response characteristics of acceleration, displacement, internal force, and strain of the structure under earthquake excitations are gained, which can provide test data and basis to evaluate the seismic performance of this CFST arch bridge or other similar structural system design.

scholarly journals Shaking Table Test and Numerical Verification for Free Ground Seismic Response of Saturated Soft Soil

2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Xuelei Cheng ◽  
Chunyi Cui ◽  
Zongguang Sun ◽  
Jinhong Xia ◽  
Guangbing Wang
Keyword(s):  
Numerical Simulation ◽  
Seismic Response ◽  
Effective Stress ◽  
Shaking Table Test ◽  
Soft Soil ◽  
Pressure Ratio ◽  
Free Field ◽  
Shaking Table ◽  
Response Characteristics ◽  
Fully Coupled

This paper investigates shaking table test (1g) and numerical simulation (fully coupled) of vertically propagating shear waves for saturated soft free field. A large-scale shaking table model test was performed to study seismic response characteristics of saturated soft soil free field. According to test results of seismic response features of free field system in saturated soft soil, the free field nonlinearity fully coupled numerical model of dynamical effective stress of saturated soft soil was established using OpenSEES, based on the u-p formulations of dynamic consolidation equation as well as effective stress solution method for saturated two-phase media. The numerical simulation of the free field seismic response of saturated soft soil under various test conditions was performed and the calculated results were compared with the shaking table test results. The results show the following. (1) With the increase of input ground motion intensity, the characteristic frequency of the saturated soft free ground decreases and the damping ratio increases gradually. (2) The saturated soft soil ground has short period filtering and long period amplification effect on the horizontal input seismic loads. The failure foundation takes on the isolation and shock absorption under strong ground motions. (3) The peak pore pressure ratio of the saturated soft soil ground is located in the shallow buried soil layer, and with the increase of the input ground motion intensity, the advantage of dynamic pore pressure ratio in this area is gradually weakened. (4) The numerical simulation results are consistent with the results of the shaking table test. This fully coupled effective stress numerical method can reasonably simulate the seismic response characteristics of free field in saturated soft soil, which lay the foundation for other more complex parameter extrapolation models of saturated soft soil sites. This research can provide the necessary technical experience for experimental study on non-free field.

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