This paper presents the effect of reinforced high performance concrete (HPC) in EXTERIOR BEAM-COLUMN JOINT with and without FIBRE under MONOTONIC LOADING. In this experimental investigation, cross-diagonal bars have been provided at the JOINT for reducing the congestion of reinforcement in JOINTs, and also M75 grade of concrete with optimum mix proportion of 10 % silica FUME and 0.3 % GLASS FIBRE was used. Four EXTERIOR BEAM-COLUMN JOINT sub-assemblages were tested. The specimens were divided into two types based on the reinforcement detailing.Type A comprises two JOINT sub-assemblages with JOINT detailing as per construction code of practice in India (IS 456-2000), and Type B comprises two JOINT subassemblages with JOINT detailing as per ductile detailing code of practice in India (IS 13920-1993). In each group there was one specimen of control mix and the remaining one specimen of FIBRE-reinforced mix. All the test specimens were designed to satisfy the strong column–weak beam concept. The performances of specimens were compared with the control mix and the FIBRE-reinforced mix. The results show that EXTERIOR BEAM-COLUMN JOINT specimens with silica FUME and GLASS FIBRE in the HPC mix showed better performance.

The fracture of High Performance Concrete (HPC) occurs in a. very explosive manner without previously exhibiting any cracking pattern as a warning. By using special FIBRE cocktails, (combinations of steel and polypropylene FIBREs) the explosive failure behaviour of High Performance Concrete (HPC) may be avoided. With the variation of cocktail composition different seismic performance of the material could be adjusted. An experimental programme has been carried out to compare the behaviour of high performance concrete and cocktail FIBRE reinforced high performance concrete beam column JOINT under reversed cyclic LOADING. HPC mix has been designed to obtain a concrete grade of M 60.The mix was designed based on modified ACI 211 method suggested by M.S. Shetty [1]. Five numbers of EXTERIOR BEAM-COLUMN JOINTs modeled to one fourth of a prototype of a building [10], designed according to Bureau of Indian Standards were cast and tested under reversed cyclic LOADING. The first specimen was made with high strength concrete and designed as per IS 456:2000 [16] and reinforced accordingly without considering the seismic requirement. The second specimen was made with high strength concrete and reinforcements in the beam column JOINT portion was detailed according to IS 13920-1993 [17], for seismic requirements. The remaining three specimens were similar to the first one but various combinations of cocktail FIBRE concrete in the JOINT region (constant %(1.5) of steel FIBRE and 0 to 0.4% of polypropylene FIBRE) were used. The cocktail fiber combinations of 1.5% of steel FIBRE and 0.2% of polypropylene FIBRE have best performance considering the strength, energy dissipation capacity, and ductility factor. Results indicate that the addition of polypropylene FIBRE to the steel FIBRE is optimum for a percentage of 0.2, which have more energy absorbing capacity, less JOINT rotation, more shear strength, more curvature ductility factor and less reinforcement strain.

The fracture of High Performance Concrete (HPC) occurs in a very explosive manner without previously exhibiting any cracking pattern as a warning. By using special FIBRE cocktails, (combinations of steel and polypropylene FIBREs) the explosive failure behaviour of High Performance Concrete (HPC) may be avoided. With the variation of cocktail composition different seismic performance of the material could be adjusted. An experimental programme has been carried out to compare the behaviour of high performance concrete and cocktail FIBRE reinforced high performance concrete beam column JOINT under reversed cyclic LOADING. HPC mix has been designed to obtain a concrete grade of M 60. The mix was designed based on modified ACI 211 method suggested by Shetty [1]. Five numbers of EXTERIOR BEAM-COLUMN JOINTs modeled to one fourth of a prototype of a building [2], designed according to Bureau of Indian Standards were cast and tested under reversed cyclic LOADING. The first specimen was made with high strength concrete and designed as per IS 456:2000 [3] and reinforced accordingly without considering the seismic requirement. The second specimen was made with high strength concrete،designed as per 1893 (Part I) 2002 [4] and reinforcements in the BEAM-COLUMN JOINT portion was detailed according to IS 13920-1993 [5], for seismic requirements. The remaining three specimens were similar to the first one but various combinations of cocktail FIBRE concrete in the JOINT region (constant % (1.5) of steel FIBRE and 0 to 0.4 % of polypropylene FIBRE) were used. The cocktail FIBRE combinations of 1.5% of steel FIBRE and 0.2% of polypropylene FIBRE have best performance considering the strength, energy dissipation capacity, and ductility factor. Results indicate that the addition of polypropylene FIBRE to the steel FIBRE is optimum for a percentage of 0.2, which have more energy absorbing capacity, less JOINT rotation, more shear strength, more curvature ductility factor and less reinforcement strain.

This paper is devoted to assess the behavior of the EXTERIOR concrete BEAM-COLUMN connections reinforced with GLASS Fiber Reinforced Polymers (GFRP) bars under cyclic LOADING. For this purpose, 8 different BEAM-COLUMN connections were experimentally investigated. In these specimens, concrete with compressive strength of 30 and 45 MPa was employed. In four of these connections, GFRP bars were used while the others were reinforced with steel bars. The confinement of longitudinal bars was different in the connections. The GFRP-reinforced BEAM-COLUMN connection showed an elastic behavior with very low plasticity features under cyclic LOADING. This resulted in lower energy dissipation compared to the steel-reinforced BEAM-COLUMN connections. The GFRP-reinforced BEAM-COLUMN connections showed lower stiffness than that of the steel-reinforced BEAM-COLUMN connections. Load-story drift envelope for specimens with GFRP bars showed an acceptable drift capacity. These specimens had the essential requirements for acting as a member of a moment frame in seismic regions. In case of GFRP strengthened specimens with low and high strength concrete, increasing the cyclic LOADING results in flexural failure of the beam in the BEAM-COLUMN connection region. Increasing the confinement of concrete beams leads to the reduction of crack width. Furthermore, at higher drifts, spalling was not observed in concrete surface in BEAM-COLUMN connection region. In the analytical parts of the study, specimens were simulated using the SeismoStruct software. Experimental and analytical results showed a satisfactory correlation.

BEAM-COLUMN connections with non-seismic detailing in buildings with moment resisting lateral load bearing systems, are the major cause of post-earthquake damage. The optimal shape and energy absorption of the moment frame structure is dependent on the design and perfect execution of the BEAM-COLUMN connections. In the BEAM-COLUMN connections, the lack of positive reinforcement of the beam in the JOINT area and non-extension of the column stirrup in the JOINT area are common defects of the JOINTs in accordance with new regulations. In this study, finite element models with seismic and non-seismic detail were considered and validate with laboratory tests by considering sliding effect of longitudinal beam reinforcement using modified steel stress-strain curve. Then, the effect of different lateral beam conditions around the JOINT was considered. The results showed well that the finite element model is more consistent with the experimental results when considering the slip effects of the longitudinal beam reinforcement. Also comparing the results of the models with the different lateral beam conditions showed that confining the non-seismic JOINTs can increase the JOINT strength against lateral loads.

The unique behavior of carbonate sediments under shear LOADING has stimulated in investigating of their geological and engineering properties. Their shapes are very different varying from needle shaped to platy shaped. Hence, it is important to examine their fabric effect on soil response under shearing condition. To this aim a series of small scale laboratory element testing were carried out on North Cornwall Rock" beach sand. Non-cemented and cemented Carbonate sand response under compression and extension LOADING and different initial density and confining pressure with samples allowed to be drained were investigated and compared. The results show that the sand shear strength under Extension LOADING is lower than compression regarding to anisotropic fabric due to platy and needle shape of grains. The anisotropy is reduced with increasing the confining pressure and initial relative density with non-cemented sand. Furthermore, present of cement bounds reduces the anisotropy especially in low confining pressures.

The unique behaviour of carbonate materials under shear LOADING has stimulated in investigating of their geological and engineering properties.Carbonate soils composed of calcium or other carbonates and most abundant in tropical marine environments are of interest from geotechnical view, especially for offshore engineers engaged with Fossil-based fuel exploitation. This was initiated in the early 1960's, when the first offshore borings in the Persian Gulf identified layers of calcarenite and thick layers of sand containing visible shell fragments.For the purpose of exploiting gas and oil resources in hot and temperate climates (e.g. Persian Gulf) off-shore structures have been placed on carbonate soils. The carbonate sediments are high crushable compared with low crushable sediments such as quartzic soils.To examine the crushability of these problematic sediments a series of MONOTONIC compression, extension and post-cyclic triaxial tests under different densities and confining pressures was carried out to study the crushing behaviour of "Rock" carbonate sand obtained from Cornwall, England.It was shown that crushing coefficient decreases with increasing in maximum principal effective stress ratio for both loose and dense states. It seems that for skeletal carbonate sand maximum and minimum dry densities will be changed during shearing LOADING. In other words, even though the sample has experienced an increase in density, it may also have experienced a reduction in relative density.

Mixed clayey soils comprising cohesive and granular materials exist extensively in nature. The fabric of these soils depends very much on the relative volume of granular materials to cohesive soils.Considering broad application of such soils in geotechnical engineering projects, their mechanical behavior and characteristics should be studied and identified. For this purpose, a set of undrained isotropically consolidated triaxial tests with MONOTONIC LOADING carried out on a number of mixed clayey soil samples with different percentages of sands and gravels. The results of the tests showed that shear. Strength and excess pore water pressures increase as the sand/gravel content in the specimens increases.For the specimens with equal volume granular contents, shearing-induced excess pore water pressures are higher when the size of the grains decreases (sand versus gravel). The results also showed that the secant modulus of deformation of the specimens increases with increasing the sand (gravel) content.