The main port in Port-au-Prince suffered extensive damage during the earthquake, inhibiting the delivery of relief supplies. The collapse of the North Wharf appears to have been caused by liquefaction-induced lateral spreading. The westernmost 120 meters (400 ft) of the South Pier collapsed, and approximately 85 percent of the vertical and batter piles supporting the remaining section were moderately damaged or broken. The remaining section of pier was shut down to vehicle traffic following additional damage that occurred during an aftershock. The collapse of a pile-supported pier at the Varreux Terminal resulted in the deaths of about 30 people working on the pier at the time of the earthquake. Less severe damage, including a small oil spill, occurred at a marine oil terminal located near Port-au-Prince. Damage to Institutions The functioning of the government and social infrastructure was seriously deteriorated by the loss of personnel, records, and facilities. Such losses occurred in numerous clinics, hospitals, police stations, schools, universities, palaces, ministries, and churches. These losses have compromised the recovery and reconstruction efforts. Conclusions The massive human losses in this earthquake can be attributed to a lack of attention to earthquake-resistant design and construction practices and the poor quality of much of the construction. The historical pattern of earthquakes in Haiti indicates that an earthquake of magnitude 7 or larger could strike southern Haiti near Port-au-Prince at any time. Reconstruction must therefore be based on sound, simple, and cost-effective engineering practice for all possible natural hazards. These principles must be clearly communicated to the citizens of Haiti. Additional fact gathering is needed, both to quantify the January 12th fault rupture and earthquake history (inputs to calculations of future earthquake probabilities), and to more comprehensively evaluate damage to buildings and infrastructure, so as to inform decisions about reconstruction.

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SUMMARY Base isolation systems generally perform well under design‐level ground motions to reduce both interstory drift and acceleration demands. During a maximum considered earthquake, however, large displacements in the base level may cause pounding between the structure and perimeter moat wall, which can lead to very high acceleration in the superstructure. A phased passive control device, or ‘gap damper’, has been conceived to control base isolator displacement during extreme events while having no effect on the isolation system performance for earthquakes up to design level. It is by introducing an appropriate initial gap that the device triggers additional energy dissipation during large earthquakes to limit displacements. Various combinations of hysteretic and viscous damping mechanisms are utilized to provide desired additional energy dissipation. A numerical study that assesses the ability of various gap damper models to reduce the base displacement by at least 25% while limiting the acceleration increase at the roof level that results from the sudden engagement of a damping device is devised. The energy dissipation level provided by the damper is optimized to provide the best possible performance. For base isolation systems with effective periods of isolation in the 2.5–3.0 s range, gap damper models incorporating a viscous dashpot are very effective in controlling displacement, whereas gap dampers restricted to a hysteretic damping mechanism are ineffective. The gap damper is less effective for systems with longer periods of isolation (3.5–4.0 s) because the lower target acceleration in this range is more difficult to meet. Copyright © 2012 John Wiley & Sons, Ltd.

Summary Recent studies have indicated uncertainty about the performance limit states of seismically isolated buildings in very large earthquakes, especially if the isolator displacement demands exceed the seismic gap and induce pounding. Previous research has shown the benefit of providing phased supplemental damping that does not affect the isolation system response in a design event. A phased passive control device, or gap damper, was designed, fabricated, and experimentally evaluated during shake table testing of a quarter scale base‐isolated three‐story steel frame building. Identical input motions were applied to system configurations without a gap damper and with a gap damper, to directly assess the influence of the gap damper on displacement and acceleration demands. The gap damper was observed to reduce displacement demands by up to 15% relative to the isolated system without the gap damper. Superstructure floor accelerations increased substantially because of damper activation, but were limited to a peak of about 1.18 g. The gap damper reduces displacement most effectively if the ground motion contains one or more of the following characteristics: the spectral displacement increases with increasing period near the effective period of the isolation system, the motion is dominated by a single large pulse rather than multiple cycles at a consistent intensity, and the motion has a dominant component aligned with a major axis of the structure. Copyright © 2016 John Wiley & Sons, Ltd.

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SUMMARYThe concept of the hybrid passive control system is studied analytically by investigating the seismic response of steel frame structures. Hybrid control systems consist of two different passive elements combined into a single device or system. The hybrid systems investigated in this research consist of a ratedependent damping device paired with a rate-independent energy dissipation element. The innovative configurations exploit individual element strengths and offset their weaknesses through multiphased behavior. A nine-story, five-bay steel moment-frame was used for the analysis. Six different seismic resisting systems were analyzed and compared. The conventional systems included a special momentresisting frame (SMRF) and a dual SMRF-buckling-restrained brace (BRB) system. The final four configurations are hybrid passive systems. The different hybrid configurations utilize a BRB and either a high-damping rubber damper or viscous fluid damper. The analyses were run in the form of an incremental dynamic analysis. Several damage measures were calculated, including maximum roof drift, base shear, and total roof acceleration. The results demonstrate the capability of hybrid passive control systems to improve structural response compared with conventional lateral systems and to be effective for performance-based seismic design. Each hybrid configuration improved some aspect of structural response with some providing benefits for multiple damage measures. The multiphased nature provides improved response for frequent and severe seismic events.

The authors discuss some of the unique aspects and lessons of the New Zealand post-earthquake building safety inspection program that was implemented following the Canterbury earthquake sequence of 2010–2011. The post-event safety assessment program was one of the largest and longest programs undertaken in recent times anywhere in the world. The effort engaged hundreds of engineering professionals throughout the country, and also sought expertise from outside, to perform post-earthquake structural safety inspections of more than 100,000 buildings in the city of Christchurch and the surrounding suburbs. While the building safety inspection procedure implemented was analogous to the ATC 20 program in the United States, many modifications were proposed and implemented in order to assess the large number of buildings that were subjected to strong and variable shaking during a period of two years. This note discusses some of the key aspects of the post-earthquake building safety inspection program and summarizes important lessons that can improve future earthquake response.

The earthquake that shook Hispaniola on 12 January 2010 devastated Haiti. The damage was widespread due to uncontrolled construction, poor material quality, and lack of rigorous engineering design. Post-event reconnaissance has brought to light serious deficiencies in these areas. Residential buildings in Haiti are typically constructed by their owners, who may or may not have the skills or resources to build a structure that is earthquake-safe. Few structures are designed by engineering professionals or are inspected for quality of construction. The two most common construction materials are masonry block and reinforced concrete. Masonry blocks, concrete cylinders, and reinforcing steel were taken from Haiti and tested in the United States. The concrete and masonry were shown to be of low strength and quality. The steel samples show expected strength properties with some specimens having reduced ductility due to bending. Building performance is demonstrated by reconnaissance photographs and case studies of the structures inspected by reconnaissance team members.