2022 NORTHWEST LUZON EARTHQUAKE: FIELD OBSERVATIONS AND COMMON DESIGN AND CONSTRUCTION PITFALLS

A magnitude (Mw) 7.0 earthquake struck Abra, Philippines on 27 July 2022 and shook the provinces in Northern and Central Luzon, Philippines. This resulted in extensive structural damage in areas that had high intensity of ground shaking. This paper presents the typical damage patterns and observed construction pitfalls documented in the aftermath of the Abra earthquake. A series of rapid reconnaissance surveys using ATC-20 were conducted in severely affected areas. Extensive damage was observed among heritage structures, which are mostly unreinforced adobe, and among residential buildings made of concrete hollow blocks. Severe damage was also evident for concrete structures with soft storeys. The field survey revealed the deficiencies in materials due to the use of rounded aggregates and friable concrete hollow blocks, and problems resulting from the prevalent use of inadequate structural systems such as unsupported walls or columns in many residential buildings. These findings contribute to the development of policies, standards, and practice in seismic-resilient construction in the Philippines and in other countries where similar building stock may be present. ##################################################