Today, the railroad industry carries 40% of United States' total freight ton-miles over 100,000 bridges spanning 225,000 km (140,000 mi) rail tracks and demand for railroads will increase by 88% 2035. Railroads maintain their infrastructure to meet this ensure ability safely carry trains. However, funds are limited allocation resources operations maintenance, repair, replacement (MRR) must be conducted cost effectively. Railroad managers interested in new innovative methods efficiently...

Today, railroads carry 40% of the total freight tonnage in North America, and this demand will double next 20 years. Half American railroad bridges are over 100 years old. Measuring bridge displacements under train loading can assist quantifying safety reliability operations. However, obtaining field is often challenging due to lack fixed reference points. This research studies direct measurement reference-free dynamic using a sensing system composed one passive-servo...

According to railroad managers in North America, measuring bridge displacements under service traffic can assist quantifying the reliability and safety of an aged network. Railroad campaign monitoring consists collecting as much information possible annually inform decisions related for maintenance, repair, replacement (MRR). However, acquiring displacement data without a stationary reference frame field is often challenging during monitoring. This research proposes hybrid reference-free...

Railroads carry 40% of the U.S.’ freight tonnage. Railroad bridges are most critical component this network. Measuring transverse displacement railroad under train-crossing load is essential for safe and cost-effective operation However, bridge difficult to collect in field with traditional sensors due lack fixed reference frame. Although reference-free provide flexibility overcoming aforementioned challenge, they often fail capture pseudo-static components observed timber bridges. This...

This paper summarizes the macro-assessment of meizoseismal ground fracture experience, based on probabilistic assessment methods described in engineering practice and research status. Earthquake analysis is inevitable result scientific development, to meet people's understanding level. Statistics Chinese mainland strong frequency; proposed a simple method calculating probability, made spreadsheet. The model uses data primarily from seismic hazard commonly used data, results are acceptable,...

This paper presents the time-frequency characteristics of ground vibrations near subway stations through field tests and analyses. More than 15 vibration measurement points are set up in longitudinal transverse directions track a station. Overall, level (VLzmax) above tunnel is approximately 73 dB on border between station mainline, while it attenuates to 63 away from by 30 meters; dominant frequency mainline area 63-80 Hz. The results direction show that increases rapidly as train drives...

Building foundation elastic pad is one of the important measures for subway vibration control. In order to understand control effect on superstructure, two identical concrete test blocks were poured site near a line. Taking real load as input source strength, isolation upper mass block was compared and analyzed; At same time, influence backfill around underground building simulated analyzed. The has non negligible restraint building, improves vertical natural frequency "building pad" system,...

In order to study the influence of train operation on indoor vibration and noise under condition co-construction railway-building, spectral characteristics structure-borne their variation with speed were analyzed by on-site measurement method a track building in Beijing, which provided reference data support for evaluation control secondary radiated railway-building.

In order to meet the functional requirements, it is often necessary set transfer floor in high-rise building structure. From perspective of influence on subway-induced vibration response characteristics structure, finite element method used calculate with under excitation subway train based actual project. Through above analysis, position analyzed. The results show that level roof decrease obviously when moves up gradually, and levels most other floors are increased varying degrees. third...

To investigate the relationship between structure-borne noise and vibration of vertical concrete barriers sitting on roadside railway, time-frequency characteristics accelerations sound pressure level barrier slab under train crossing events were analyzed by in situ testing. The results show that (1) mainline area is approximately 94.7 dB, while it 104.4 dB turnout area, average increase effect 9.7 dB. (2) 66.4 dB(A), 70.0 dB(A) 3.6 dB(A). (3) amplified significantly at 40-60 Hz. In summary,...

The current equivalent linearization method for evaluation of seismic response soil layers has been widely used by engineers, but it obviously limits while considering severe earthquake action and dealing with extremely soft layers. Developing a direct time-domain integral is essential. In this paper, direct-domain proposed. the method, dynamic skeleton curve constitutive model introduced can fit test results shear modules ration damping ratio simultaneously, central difference integration...