A repair and retrofitting intervention to improve plastic dissipation and shear strength of Chinese rc bridges

Abstract

<p>In this paper a rapid repair and retrofitting technique for reinforced concrete (rc) Chinese bridges damaged by a strong earthquake, is proposed and tested. This intervention is an upgrade of the one tested with very good results during a previous experimental research on bridges designed according to the old Italian code without proper seismic details. The improvement of the repair operation consists in the use of dissipation systems to substitute the damaged rebar parts at pier base guaranteeing the correct plastic distribution in plastic hinge only. Dissipation systems with different configurations were considered to optimize the intervention. The repaired and retrofitted Italian bridge already studied in the previous research, was designed according to Chinese codes but with insufficient transversal steel reinforcement. Some pier specimens (scale 1:6) of the most stressed pier of this bridge, with and without dissipation systems, were built. A C- FRP wrapping was applied to increase the insufficient shear strength and the ductility in plastic hinge. Cyclic tests were carried out on the scaled specimens at Fuzhou University lab (China) to evaluate the effectiveness of the proposed technique.</p>

Surface Generation of Asynchronous Seismic Signals for the Seismic Response Analysis of Bridges

“…Further analyses are in progress to evaluate the seismic response of existing bridges repaired and retrofitted after strong seismic damage [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]. The seismic behavior of bridges subjected to asynchronous excitation will be defined also considering near fault earthquake [57,58] …”

Seismic Behaviour of Isolated Rc Bridges Subjected to Asynchronous Seismic Input

“…This local deformation imposes different local state of stresses which should be evaluated during the bridge design These analyses will be performed considering also different bridge geometries and earthquake inputs. The new selected cases of study will include also some existing bridges repaired and retrofitted after strong seismic damage by some new rapid techniques [40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55]. The seismic behavior of bridges subjected to asynchronous excitation will be defined also considering near fault earthquake [56,57].…”

Ultra-High-Performance Fiber-Reinforced Concrete Jacket for the Repair and the Seismic Retrofitting of Italian and Chinese Rc Bridges

“…This fiber content was selected to build a HSF jacket with a shear strength sufficient to retrofit the damaged pier specimen [22], [23].…”

“…Each procedure repairs the damaged longitudinal rebar parts by partial substitution using new shaped rebar parts [22]- [25]. A strong connection system connects these new rebar parts to the undamaged original ones (anchorages and undamaged rebar part outside the plastic hinge).…”