Nor Hayati Abdul Hamid

Comparing the Seismic Performance of Beam-Column Joints with and without SFRC when Subjected to Cyclic Loading

The experimental work on two full-scale precast concrete beam-column corner joints with corbels was carried out and their seismic performance was examined. The first specimen was constructed without steel fiber, while second specimen was constructed by mixed up steel fiber with concrete and placed it at the corbels area. The specimen were tested under reversible lateral cyclic loading up to ±1.5% drift. The experimental results showed that for the first specimen, the cracks start to occur at +0.5% drifts with spalling of concrete and major cracks were observed at corbel while for the second specimen, the initial cracks were observed at +0.75% with no damage at corbel. In this study, it can be concluded that precast beam-column joint without steel fiber has better ductility and stiffness than precast beam-column joint with steel fiber. However, precast beam-column joint with steel fiber has better energy dissipation and fewer cracks at corbel as compared to precast beam-column joint without steel fiber.

Retrofitting of a Double Unit Tunnel Form Building Using Additional RC Wall, Steel Angle and CFRP

Tunnel form construction is widely known as modern construction method that enables the construction of horizontal and vertical elements simultaneously. It is quickly construct low cost, high quality and earthquake safe to construct cellular buildings. Main objective of this study is to determine the seismic retrofitting performance of a double unit tunnel form building when retrofitted using additional RC wall, steel angle and Carbon Fiber Reinforced Polymer (CFRP) when tested under in-plane lateral cyclic loading. A comparison of tunnel form building was made before and after retrofitting in terms of lateral strength, stiffness, ductility and equivalent viscous damping. Result indicates that retrofitting method using additional RC wall, steel angle and CFRP was able to increase the lateral strength, ductility and equivalent viscous damping under in-plane lateral cyclic loading. The result also shows the effectiveness of additional RC wall, steel angle and CFRP in improving the shear resistances and deformation capacities of concrete structures and delaying their stiffness degradation under earthquake loading.

Seismic performance and assessment of precast beam-column corner joint subject to reversible lateral cyclic loading

A seismic performance of full-scale precast reinforced concrete beam-column corner joint with corbel was examined in the laboratory. The precast beam-column joint designed using BS8110:1:1997 was tested under lateral cyclic loading up to +1.5% drift. Displacement ductility of precast beam-column joint with corbel was determined. The visual observation showed that the damage occurred at the corbel of beam-column joint. Major cracks were also observed at the cast-in-place area above the joint area. In this paper, the damage state of the specimen is categorized in accordance to HAZUS®99 and the vulnerability of the specimen was assessed using fragility curve.

Retrofitting of Single Unit Tunnel Form Building Using Steel Plate under Out-of-Plane Lateral Cyclic Loading

A one-third scale single unit of 3-storey tunnel form building with foundation beam was designed, constructed and tested under out-of-plane lateral cyclic loading. This building was designed according to BS8110 with no provision for seismic loading. Tunnel form building was initially tested at ±0.01% , ±0.1%, ±0.25%, ±0.5%, ±0.75%, ±1.00%, ±1.25% and ±1.5% drifts until the structure lost its lateral strength (strength degradation). Then, the specimen was repaired and retrofitted using steel plate and angle which was positioned at the wall-slab joints that had suffered severe damages. A similar drift of displacement before retrofitting was repeated for the specimen after being retrofitted. Visual observation of damages, hysteresis loops, stiffness, ductility and equivalent viscous damping (EVD) of the specimen were analyzed and compared before and after retrofitting. The proposed retrofitting technique has increased its lateral strength by 26%. Fewer cracks occurred after retrofitting the specimen compared to before retrofitting. It can be concluded that steel plate and angle can strengthen the wall-slab joint and this method can be used to retrofit the tunnel form building if it had been damaged caused by earthquake excitations.

Comparison of Seismic Behaviour for a Single Unit Tunnel Form RC Building before and after Repaired

Repairing and strengthening the structures are gaining more attention from many researchers and structural engineers after the structures suffered damages from natural disasters. Tunnel form RC buildings which are not designed according to seismic code of practice are very vulnerable to ground motion when located to near field earthquake. This paper presents the method of repair and strengthening of 3-storey tunnel form building subjected to in-plane lateral cyclic loading. The building was strengthened using the combination method of steel angle, steel plate and Carbon Fiber Reinforce Polymer (CFRP) sheet. The results show that the lateral strength capacity is increase by 15.66%, ductility increase by 53.57% and equivalent viscous damping increase by 28.88% for the first cycle and 33.65% for the second cycle. However, the stiffness of the structure reduce by 56.6%. It can be concluded that this method can be adopted for the damage of tunnel form building system.

Seismic Performance of Insulated Sandwich Wall Panel Subjected to Lateral Cyclic Loading

In this paper, the seismic performance of the insulated sandwich wall panel is studied. Two samples W1 and W2 of Insulated Sandwich Wall Panel (ISWP) were tested under in-plane lateral cyclic loading. The difference between W1 and W2 is the numbers of wall plug used in order to hold the specimen in standing parallel position. Four wall plugs used for W1 meanwhile eleven wall plugs used for W2. ISWP is placed axially on top of the foundation beam. The concrete block is slotted on top of the wall panel as load transfer from the roof. The aspect ratio of the specimen is Ar = H/B = 1.97 and slenderness ratio is λ = H/t = 36.92. The testing is conducted with small percent of drift which is 0.1% and continued with 0.2%. The drift was increased gradually about 0.2% until reach ±1.0%. Furthermore, the specimen was tested with an increment of ±0.2% drift until the specimens reach the strength capacity. The experimental results showed that for the first specimen, the wall panel behaves elastically up to 0.4% drift before yielding. Due to loading and unloading condition, the aluminium frame that used along the perimeter of the wall panel buckled at 1.2% drift. For the second specimen the wall panel behaves elastically up to 0.4% drift before yielding. Once 0.6% drift applied, crack started to appear at the connection joint between G.I channel and foundation beam. The analysis of the result from the graphs of hysteresis loop for both W1 and W2 were presented by considering the seismic parameter such as stiffness, ductility and equivalent viscous damping.

Assessment of precast beam-column using capacity demand response spectrum subject to design basis earthquake and maximum considered earthquake

Malaysia is surrounded by the tectonic feature of the Sumatera area which consists of two seismically active inter-plate boundaries, namely the Indo-Australian and the Eurasian Plates on the west and the Philippine Plates on the east. Hence, Malaysia experiences tremors from far distant earthquake occurring in Banda Aceh, Nias Island, Padang and other parts of Sumatera Indonesia. In order to predict the safety of precast buildings in Malaysia under near field ground motion the response spectrum analysis could be used for dealing with future earthquake whose specific nature is unknown. This paper aimed to develop of capacity demand response spectrum subject to Design Basis Earthquake (DBE) and Maximum Considered Earthquake (MCE) in order to assess the performance of precast beam column joint. From the capacity-demand response spectrum analysis, it can be concluded that the precast beam-column joints would not survive when subjected to earthquake excitation with surface-wave magnitude, Mw, of more than 5.5 ...

Comparison of Seismic Performance Between Interior Beam-Column Joint Designed Using BS8110 and Eurocode 8

This paper investigates the seismic performance differences between interior beam-column joint which designed with BS8110 and Eurocode 8 of a two-storey precast school building. Both specimens were designed, constructed and tested under in-plane lateral cyclic loading. Subsequent to testing, the interior beam-column joint designed using BS8110 experienced diagonal shear cracks at top of column while the joint designed using EC8 only suffered hairline cracks at beam-column interface. Overall seismic performance comparison shows that beam-column joint designed with EC8 has higher in-plane lateral strength, lateral displacement, stiffness, ductility and equivalent viscous damping than joint beam-column joint designed with BS8110. The maximum drift achieved by seismic joint is 2.25 % and non-seismic joint has maximum drift of 1.15 %. It can be concluded that the seismic joint has perform better than non-seismic joint due to the fact that more percentage of longitudinal and transverse reinforcement were used in seismic joint.

Experimental hysteresis loops validation using HYSTERES program for beam-column joints under lateral cyclic loading

This paper provides the comparison and validation between experimental and modeling results of three full-scaled emulative cast-in-place beam-column joints with corbels. The beam-column joints consist of corner, interior and exterior sub-assemblages, which represent connection elements in a two-storey existing precast school building. The sub-assemblages were designed in accordance to BS8110 which do not consider earthquake loading and tested in the laboratory under reversible lateral cyclic loading with specified inter-story drift. Load versus displacement curve (hysteresis loops) were generated for all three specimen tested from the experimental data obtained. Ruaumoko HYSTERES Program was implemented to model the experimental results. By using Pampanin Reinforced Concrete Beam-Column Joint Hysteresis rule with reloading slip factor, load versus displacement curves for corner, interior and exterior beam-column joints were generated. The modeling results were compared with the load versus displacement cu...

Assessment of precast beam-column exterior joint subject to Design Basis Earthquake (DBE) and Maximum Considered Earthquake (MCE) using fragility curve

The performance based seismic design requires a probabilistic approach to enable the designers/engineers to predict the damage state of a structure following an earthquake. Fragility curve was developed in this paper for precast beam-column exterior joint to fulfil the needs of the probabilistic approach. The displacement ductility obtained from the experimental work was used to identify the damage state levels for the development of fragility curve for the beam-column exterior joint specimen. The damage state levels are described in accordance with the definitions given by FEMA 273 and HAZUS®99. Nonetheless, the prediction of damage states and the color-coding system of the precast beam-column exterior joint were made for two different levels of earthquake excitation based on the Design Basis Earthquake (DBE) and Maximum Considered Earthquake (MCE) which were obtained from the Malaysian Seismic Hazard Maps. The color-coding system was utilized to identify the performance level, damage level, drift damage...