@article {bnh-4692, title = {Seismic retrofit of exterior RC beam-column joint using diagonal haunch}, journal = {Engineering Structures}, volume = {174}, year = {2018}, month = {01/2018}, abstract = {

Exterior beam-column joint is typically the weakest link in a limited-ductile RC frame structure. The use of diagonal haunch element has been considered as a desirable seismic retrofit option for reducing the seismic demand at the joint. Previous research globally has focused on implementing double haunches, whilst the performance of using single haunch element as a less-invasive and more architecturally favourable retrofit option has not been investigated. In this study, the feasibility of using a single haunch system for retrofitting RC exterior beam-column joint is explored. This paper presents the derivation of the key formulations for the implementation of a single diagonal haunch as well as the generalization of the formulations for all three systems: the non-retrofitted subassembly, the double haunch retrofitting system, and the single haunch retrofitting system. The formulations have then been validated by available experimental data for non-retrofitted subassembly and double haunch retrofitting system. Finally, the effectiveness of the single haunch retrofitting system is compared with that of the double haunch retrofitting system through a parametric study.

}, keywords = {Exterior beam-column joint, limited-ductile, RC frame, Seismic retrofit, Single diagonal haunch.}, doi = {10.1016}, url = {https://www.sciencedirect.com/science/article/pii/S0141029617328857}, author = {Zabihi, Alireza and Hing-Ho Tsang and Emad F Gad and John Wilson} } @conference {bnh-6008, title = {Retrofitting RC Beam-Column Joint in Australia using Single Diagonal Haunch}, booktitle = {Australian Earthquake Engineering Society 2016 Conference}, year = {2016}, month = {11/2016}, publisher = {Australian Earthquake Engineering Society}, organization = {Australian Earthquake Engineering Society}, address = {Melbourne}, abstract = {

Exterior beam-column joint is potentially the weakest link in a limited-ductile RC frame structure in Australia. The use of diagonal haunch element has been considered as a desirable seismic retrofit option for preventing brittle failure of the joint. Previous research globally has focused on implementing double haunches, whilst the performance of using single haunch element as a less-invasive and more architecturally favourable retrofit option has not been investigated. In this study, the feasibility of using a single haunch system for retrofitting RC beam-column joint in Australia is explored. This paper presents the key formulations of the technique and illustrates its effectiveness by showing analytically the changes in the shear demand at the joint.

}, keywords = {Exterior beam-column joint, limited-ductile, RC frame, seismic retrofitting, single haunch}, author = {Zabihi, Alireza and Hing-Ho Tsang and Emad F Gad and John Wilson} } @conference {bnh-1890, title = {Seismic Performance of Typical C-Shaped Reinforced Concrete Shear Cores in Australia}, booktitle = {Australian Earthquake Engineering Society Conference 2014}, year = {2014}, abstract = {

Limited-ductile reinforced concrete structures have been known to perform poorly when subjected to large seismic ground motions. Many buildings in Australia rely on reinforced concrete shear-cores as their primary lateral load resiting system, but these are only required to have a low standard of detailing as per the current concrete material standards AS 3600. While there is some literature available on the numerical and analytical modelling of rectangular shaped shear walls, non-rectangular shear walls have not been extensively analysed. {\textquotedblleft}C-shaped{\textquotedblright} shear walls are commonly found enclosing a service core, lifts, stairs and toilets. This paper presents a study which looks at the seismic performance of C-shaped shear walls with different steel reinforcement ratios for low, mid and high-rise buildings. The current earthquake actions code AS 1170.4 has been used for a preliminary design of the walls using a force-based design approach within which the intention is to satisfy the performance objective of life safety in a 500 year return period earthquake design level event in Melbourne. The displacement capacity of these different core walls has been calculated using a Displacement-Based Assessment procedure and complemented with finite element modelling program SeismoStruct. The results of a probabilistic seismic hazard analysis (PSHA) using the AUS5 recurrence model that has been conducted for the city of Melbourne has been used to calculate more accurate predictions of the displacement response spectra for 500 and 2500-year return periods. The C-shaped core walls have then been assessed by comparing the displacement capacity at different structural performance limit states to the displacement spectra derived from the current earthquake loading code AS 1170.4 and the spectra results from the PSHA for both the 500 and 2500-year return periods and for soil classes Be and De.

}, keywords = {AUS5, Australia, capacity, concrete, Core, displacement-based, earthquake, limited-ductile, low-to-moderate, PSHA, seismicity, spectra, unconfined, Walls}, author = {Ryan D. Hoult and Helen M. Goldsworthy and Elisa Lumantarna} }