Justin D. Marshall

Recipe for Disaster: Construction Methods, Materials, and Building Performance in the January 2010 Haiti Earthquake

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.

Post-Earthquake Building Safety Inspection: Lessons from the Canterbury, New Zealand, Earthquakes

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.

Structural and Non-Structural Damage to Industrial Facilities during the February 2011 Christchurch, New Zealand, Earthquake

The aftershock that struck Christchurch, New Zealand on February 22, 2011 had a significantly smaller magnitude and duration than the September event in the same region, although the damage was much more significant. This paper explores the damage, both structural and non-structural, to low-rise, industrial buildings, primarily those with precast concrete cladding. Industrial buildings observed in and around Christchurch were typically comprised of either load bearing tilt-up panels with steel roof framing, or pre-engineered steel frames with pre-cast cladding panels. At buildings with load-bearing tilt-up panels, damage was observed in the panels as well as the connection between the panels and roof framing members. Buildings with steel frames supporting gravity loads and tilt-up panels for lateral resistance experienced damage in the connections between the precast and steel columns that were not designed for the required deformation. Recommendations for connections with better performance are suggested. Non-structural damage due to ground shaking and geotechnical damage is also discussed.

Dynamic Response of Steel Moment-Frame Structures with Hybrid Passive Control Systems

The concept of the hybrid passive control system is studied analytically by investigating the seismic response of steel moment-frame structures. A hybrid passive system combines a rate-dependent damping device with a rate-independent energy dissipation device. The innovative configuration exploits individual element strengths and offsets their weaknesses through multi-phased behavior. A 9-story, 5-bay steel moment-frame was used for the analysis. Six different seismic resisting systems were analyzed and compared. The conventional systems included a plain special momentresisting frame (SMRF) and a dual SMRF-buckling-restrained brace (BRB) system. The four hybrid configurations utilize a BRB and either a high-damping rubber damper or viscous fluid damper. The results demonstrate the capabilities of hybrid passive control systems to improve structural response compared to conventional lateral systems and to be effective in performance-based earthquake engineering. Each hybrid configuration improved some aspect of structural response with some providing benefits for multiple damage measures. The multi-phased nature of the device improves performance for small, moderate and severe seismic events.

Single-Degree-of-Freedom Characterization of Multi-Phase Passive Control Systems

A Multi-phase Passive Control System (MPCS) combines two passive control devices in order to offset the individual weaknesses and enhance structural performance, allowing the structure to respond effectively to varying levels of loading. Previous work involving a nine-story frame demonstrated the effectiveness of MPCSs but the fundamental understanding of the system was lacking. In order to more clearly understand the behavior and identify important parameters and parameter interactions, a single-degree-of-freedom (SDOF) non-linear dynamic study was performed. The results offer significant insight towards developing structural systems adaptable to multi-objective performance-based design procedures that meet higher performance standards than for ductility-based design.

Full-Scale Testing of Three-Sided Precast Concrete Arch Sections

The use of precast, three-sided arch culverts has become popular for new and replacement short-span bridges because of rapid construction time and minimal environmental impact on the waterway. The arching action in the top slab creates a horizontal thrust, and the surrounding fill enables lateral earth pressures to develop in the backfill based on this thrust. The lateral pressure behind the legs potentially permits the bridge to carry larger loads than it could without backfill confinement. This paper reports the results of three full-scale tests of three-sided culverts. The first test consists of a field test using an overload vehicle on a site with a newly constructed, 12.8-m clear-span, three-sided, precast arch bridge. The second specimen, an individual 6.1-m arch section, was tested in the laboratory for service-level loading in two configurations. One unrestrained configuration and one setup with steel sections simulating lateral restraint at two points along the wall were tested; additionally, the 6.1-m arch specimen was tested to failure without lateral restraint. The third specimen, an 11.0-m clear-span arch section, was tested to failure without any lateral restraint. The results of the three full-scale tests are presented and discussed. In addition, nonlinear models were calibrated with the experimental tests and then analyzed with the factored design loads to determine whether the demand, including nonlinear effects within the section, exceeded the arch section capacity.

PERFORMANCE OF STRUCTURES IN THE JANUARY 2010 MW 7.0 HAITI EARTHQUAKE

The earthquake that shook the island of Hispaniola on January 12, 2010 devastated Haiti. The resulting damage was widespread due to the construction methods, poor material quality and lack of rigorous design procedures. Post-event reconnaissance has brought to light deficiencies in all these areas. Construction, especially residential, is typically completed by the building owner who may or may not have the necessary skills to design or build safe structures. Very few structures are designed by an engineering professional. The two most common construction materials are masonry block and reinforced concrete. Building response to the ground shaking is demonstrated through damage surveys in downtown Port-au-Prince and Leogane and specific case studies generated through reconnaissance efforts which highlight the infrastructure problems which led to the deadly structural performance.