Spreading-Induced Damage to Short-Span Bridges in Christchurch, New Zealand

Abstract

This paper discusses the performance of road bridges during the 2010–2011 Canterbury earthquakes and focuses on the response of bridges in liquefying soils undergoing lateral spreading. A characteristic spreading-induced mechanism for short-span bridges with rigid superstructures is presented and explored using four well-documented case studies. A series of pseudo-static analyses are then used to investigate the observed response of the bridges and their pile foundations in particular. Deformations and damage to the piles are evaluated and correlated with the spreading displacements, and key factors controlling the pile response and the development of the spreading-induced damage mechanism are identified.

Fines-content effects on liquefaction hazard evaluation for infrastructure in Christchurch, New Zealand

“…The CES initiated with the M w 7.1, 4 September 2010 Darfield earthquake and was punctuated by the M w 6.2, 22 February 2011 Christchurch earthquake, each of which induced pervasive and damaging liquefaction. Observed manifestations of liquefaction included, among others: (1) spreading-and settlement-induced damage to bridges and bridge approaches (e.g., [58,20]); (2) widespread loss of road functionality due to cracking and fissuring of pavements and inundation by liquefaction ejecta (e.g., [17]); (3) failure of buried lifelines due to flotation or differential settlements, to include water and wastewater distribution systems (e.g., [44]), electric power networks (e.g., [34]), and communication lines (e.g., [53]); (4) damage to levees (stopbanks) caused by spreading, Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/soildyn slumping, and settlement (e.g., [23]); (4) impairment of port structures caused by ground deformations, to include wharfs, seawalls, and fuel lines (e.g., [13]); (5) slumping-and spreadinduced damage to railway embankments (e.g., [17]); and (7) settlement and tilting of residential homes, commercial properties, and high-rise structures, resulting in widespread loss of building stock (e.g., [9]). In addition to direct effects on infrastructure, the $500,000 t of liquefaction ejecta collected throughout Christchurch posed a threat to stormwater systems and to human health if left unmanaged [57].…”

Shake‐table investigation of scoured RC pile‐group‐supported bridges in liquefiable and nonliquefiable soils

“…Although in-situ blast experiments are probably the most realistic way to represent behaviors of piles under shaking-induced liquefaction, limited funds and difficulties in blast techniques that trigger soil liquefaction impede their widespread applications. [30][31][32] To date, due to inherent complexities of soilstructure interaction and liquefaction, studies on seismic failure mechanism of bridges in liquefied soils are still warranted. Compared with centrifuge and in-situ tests, the one-g shake-table test tends to be a compromise choice since it is relatively economic and feasible, and capable of representing inelastic behavior of RC structures as well as soils.…”

Aspects of bridge‐ground seismic response and liquefaction‐induced deformations

“…1. As highlighted in earlier studies, 9,22,27,28 response is highly dependent on the bridge-ground system as an integral global entity. Connectivity provided by the bridge deck, soil profile variability along the bridge length, and geometric configuration of the slopes are all factors that can significantly influence the outcome.…”

“…Specific observations and conclusions include: As highlighted in earlier studies, response is highly dependent on the bridge‐ground system as an integral global entity. Connectivity provided by the bridge deck, soil profile variability along the bridge length, and geometric configuration of the slopes are all factors that can significantly influence the outcome. Particularly for pulse‐type seismic motions, local slope deformations may be superposed on an overall global pattern of permanent lateral ground motion, which might contribute to higher demands due to the combined outcome of both. The bridge structure and its foundations exerted a significant restraining effect on lateral ground deformations.…”

“…[1][2][3][4] Damage to such bridges has been observed in reconnaissance investigations, including the recent 2010 Maule [5][6][7] and the 2011 Christchurch earthquakes. [8][9][10] From these investigations, observed response was often noted to be highly influenced by the global bridge-ground overall characteristics as an integral system.…”