Seismic performance of a continuous bridge with winding rope device activated by a fluid viscous damper

The seismic requirements of piers with fixed bearings (the fixed pier) for continuous girder bridges are relatively high, while the potential seismic capabilities of piers with sliding bearings (the sliding piers) are not fully utilized. To solve this contradiction, a new type of winding rope shock absorption device activated by a fluid viscous damper (WRD-D) was proposed. The WRD-D was installed on the top of the sliding piers, and the both ends of a fluid viscous damper were connected to the superstructure by winding ropes. During an earthquake, the damping force rises with the increase of relative speed between the sliding piers and the superstructure, activating the WRD-D and producing large frictional resistance, subsequently causing the sliding piers and the fixed pier to bear the seismic load cooperatively. In this study, the working mechanism of the WRD-D was researched. The shaking table test of a scaled continuous girder bridge model employing the WRD-D was conducted. The test results reveal that the WRD-D can effectively reduce the seismic requirements of the fixed pier and the superstructure displacements.

Failure Mechanisms and Parameters of Elastoplastic Deformations of Anchorage in a Damaged Concrete Base under Seismic Loading

The article addresses mechanisms of anchorage failure in a concrete base studied within the framework of physical experiments. The authors investigated the most frequently used types of anchors, such as the cast-in-place and post-installed ones. The anchorages were studied under static and dynamic loading, similar to the seismic type. During the experiments, the post-earthquake condition of a concrete base was simulated. Within the framework of the study, the authors modified the values of such parameters, such as the anchor embedment depth, anchor steel strength, base concrete class, and base crack width. As a result of the experimental studies, the authors identified all possible failure mechanisms for versatile types of anchorages, including steel and concrete cone failures, anchor slippage at the interface with the base concrete (two types of failure mechanisms were identified), as well as the failure involving the slippage of the adhesive composition at the interface with the concrete of the anchor embedment area. The data obtained by the authors encompasses total displacements in the elastic and plastic phases of deformation, values of the bearing capacity for each type of anchorage, values of the bearing capacity reduction, and displacements following multi-cyclic loading compared to static loading. As a result of the research, the authors identified two types of patterns that anchorages follow approaching the limit state: elastic-brittle and elastoplastic mechanisms. The findings of the experimental research allowed the authors to determine the plasticity coefficients for the studied types of anchors and different failure mechanisms. The research findings can be used to justify seismic load reduction factors to be further used in the seismic design of anchorages.

Analysis of Multistory Buildings With Stub Column In Different Seismic Zones In India – A Review

Construction of building requires proper planning and management. Buildings are subjected to various loads such as dead load, live load, wind load and seismic load. Seismic load has extreme adverse effect on building so it is necessary to perform seismic analysis. This paper explains about the response of building when it is subjected to seismic load, this response can be shown by story drift and base shear. Behavior of buildings with stub columns is analyzed and the results are compared with buildings without stub columns. Seismic analysis has been performed on (G+7) buildings located in seismic zones 2,3,4&5 using ETABS software. Analysis has been performed according to IS 1893:PartI (2002).The storey drift and design base shear are evaluated and compared. Pushover analysis was performed and the results were compared.

Dynamic Response Characteristic of Building Structure under Blasting Vibration of underneath Tunnel

The vibration induced by blasting excavation of the subway tunnel in complex urban environments may cause harmful effects on adjacent buildings. Investigating the dynamic response of adjacent buildings is a key issue to predict and control blasting hazards. In this paper, the blasting excavation of the subway tunnel right below a building was selected as a case study, and the blast vibrations in the field were monitored. The Hilbert–Huang Transform (HHT) model was used to extract and analyze the time-frequency characteristic parameters of blasting dynamic response signals. By substituting intrinsic mode functions (IMF) component frequency and instantaneous energy for main frequency and blasting total input energy, respectively, the characteristics of time-instantaneous frequency-instantaneous energy of buildings under blasting seismic load were analyzed, and the concept of effective duration of vibration was proposed.

Accounting for horizontal torsional vibrations of foundations when calculating seismic load

The article presents a method for calculating in-plane vibrations of building structures under seismic load taking into account the possibility of foundation displacement, which is similar to horizontal torsional vibrations when calculating earthquake forces. The method is illustrated by the structural design of a seven-storey tower-like building with a massive foundation. We develop transfer functions for a massive rigid body, which are subsequently used for calculating the response of the foundation subject to base shears and moments applied to the outer plane of the foundation under seismic forces. The structural calculations conducted for ductile structures with the first frequency of ~2.4 Hz and for more rigid structures with the first frequency of 7.1 Hz showed that, depending on the building stiffness, reduced seismic forces increase by 1.5–2 times. According to the results obtained, when designing structures in areas of high seismic hazard, account should be taken of possible foundation flexibility effects depending on different types of soil and structural solutions of particular buildings.

Design Calculation for A (G +10) Building (Encode Steel)

The proposed steel building at Mumbai consisting of G+10 storeys, has a built-up area of about 165m2. The typical floor height is 3m above GL and the total height of the building above GL is 33m.Withreference to given plan, the architectural drawings and structural drawings showing plan, elevation, sectional views and connection drawings are drawn by using AUTOCAD 2017.Design calculations (Dead Load, Live Load, Wind Load, Seismic Load) are calculated manually-As per IS codes which are mentioned in technical details. The rolled steel sections for beam and column has been chosen from IS 12778:2004. High tensile steel grade-E350BR has been used for steel sections. And, the analysis of structure is done by using STAAD.Pro V8i SS5.Design of beam and column are manually calculated-As per IS: 800-2007. And, spread sheet has been created to check the beam and column, whether it is safe or not. The connection designs are calculated-As per IS codes by using Welding-As per IS 9595-1996 and Fasteners-As per IS 3757-1985. Bracings are provided in the ground floor between the column to avoid soft storey failure. The material requirements are mentioned based on the design calculations. The total estimation of the building is 1.11cr.