Seismic Behavior of Strengthened Adobe Masonry Structures

Abstract

Earth quake engineering in Pakistan became popular in last few decades for both assessment and design of structures. Innovation in design codes for all structural topologies with the incorporation of seismic assessment, procedures based on identification of damage status in terms of displacement thresholds have brought revolution in the said field. Most of the rural areas in Pakistan employ Adobe and mud masonry for construction dwelling. In Pakistan, most of the rural areas use Adobe and mud masonry construction for dwelling primarily because, one, they are poor and, second, it is cheap and extreme environmental conditions favor this construction. In Baluchistan, 80% of the population is living in houses constructed of Adobe masonry. Baluchistan is an earthquake prone area and has seen many earthquakes in the past. Thus, it is essential that houses constructed in Baluchistan should be properly designed to perform well during earthquakes. Adobe and mud masonry construction did not perform well during the past earthquakes and most of the houses were severely damaged. During recent Awaran Earthquake, more than 80% of houses in earthquake hit area were completely destroyed resulting into loss of life and property. Thus, there is a need to make this type of construction better earthquake resistant. In this research, gravity load and seismic analysis of Adobe Wall Panel (12 feet x 10 feet) having 18 inches thickness and Adobe room (12 feet x 12 feet x 10 feet) was performed using commercial software SAP2000. Nonlinear Static Pushover and Nonlinear Dynamic Time History Analysis procedures were used for Seismic Analysis. First, simple Adobe Wall Panels and then Adobe room were analyzed and the weaknesses were identified. Then, Adobe Wall Panels and Adobe room strengthened with locally available Bamboos and Palm Leaves were analyzed. Lateral displacement and shear stresses were studied under all kinds of loadings.