Study on overstrength and ductility of reinforced concrete building with different infill through nonlinear analysis

The building structure with infill wall shows higher global stiffness along with the uncertain behaviour during 2015 Gorkha earthquake. It significantly increased the collapse rate of structures during earthquakes. The response of buildings with different infills during seismic excitations is not completely accounted by current seismic codes in the region. On the other hand, due to the different geological region, availability of infill materials for reinforced concrete building also differs on region to region. In most of the situations the burnt clay brick, concrete blocks and stone block are used as infill materials during building construction. In this scenario, this study explores the importance of selection of right infill material for better seismic performance during earthquakes. For this, building constructed at Pokhara Metropolitan City is considered for case study. The structural model is prepared with and without considering infills. The solid, hollow concrete block and clay brick masonry are taken as infill material during analysis. The structural behaviour during earthquakes is studied with non-linear static pushover. The result shows that the hollow concrete block masonry infill (INHB) shows better structural performance compared to other infill types.

Effective in-plane elastic properties of honeycomb-polymer composites

Honeycomb composites are now common materials in applications where high specific stiffness is required. Previous research has found that honeycombs with polymer infills in their cells, here referred to as honeycomb-polymer composites (HPCs), exhibit effective stiffnesses greater than the honeycomb or polymer alone. Currently, the state of analytic models for predicting the elastic properties of these composites is limited, and further research is needed to better characterize the behavior of these materials. In this research, a nonlinear finite element analysis was employed to perfor2m parametric studies of a filled honeycomb unit cell with isotropic wall and infill materials. A rigid wall model was created as an upper bound on the deformable wall model’s performance, and an empty honeycomb model was employed to better understand the mechanisms of stiffness amplification. Parametric studies were completed for infill material properties and cell geometry, with the effective Young’s modulus studied in two in-plane material directions. The mechanisms by which the stiffness amplification occurs are studied, and comparisons to existing analytic models are made. It has been observed that both the volume change within the honeycomb cell under deformation and the mismatch in Poisson’s ratios between the honeycomb and infill influence the effective properties. Stiffness amplifications of over 4000 have been observed, with auxetic behavior achieved by tailoring of the HPC geometry. Additionally, the effect of large effective strains up to 10% is explored, where the cell geometry changes significantly. This research provides an important step toward understanding the design space and benefits of HPCs.

A Comparative Study on Conventional Clay Bricks and Autoclaved Aerated Concrete Blocks

In India, traditional clay brick is the most common filler material used in building. The materials used in construction have a significant influence on both the constructed environment and the project’s ultimate cost. Autoclaved Aerated Concrete (AAC) has recently emerged as a viable alternative to clay and fly ash bricks. In this work, a comparison of clay bricks and AAC blocks is explored. Although AAC blocks have been utilised in building since 1924, they now account for just 16-18% of all construction in India. AAC blocks have desirable mechanical qualities in proportion to their low bulk density, improved thermal and acoustic properties, light weight, and ease of installation, making them an obvious alternative to replace traditional clay bricks. The purpose of this study is to demonstrate the potential of AAC blocks as an infill material to replace clay bricks and to encourage its usage in construction to create more energy efficient and sustainable structures. AAC blocks’ potential as an infill material in hilly areas is discussed.

Behavioural Study of Infill’s Walls on Soft Story Building

Open ground storey or soft storey is a typical feature in multistory structures in urban areas. This open storey is provided to accommodate parking, reception lobbies, office, communication hall etc. Many of structure having soft storey suffered major damage and collapsed in recent earthquakes. During an earthquake, because of variation in stiffness in soft story and its adjacent floors the inter story drift can occur and the lateral forces cannot be well distributed along the height of building. Lateral forces concentrate on soft story causes large displacement. In this work, an attempt has been made to observe the behavior of gradual decrease in stiffness of building, by using different types of infill material. This work discusses Optimum Earthquake response of tall buildings by response spectrum method as per IS 1893:2002 (Part- I) in ETAB’S software. Seismic parameters like storey stiffness and storey displacement are checked out.

Structural Behavior of Lightweight Composite Slab System

This study investigate the structural behavior of lightweight composite slab system that consist of profiled steel sheet (PSS) attached to dry board (DB) using mechanical screws and with or without infill materials. A total four full-scale panel specimen were tested under four-point bending when subjected under static loading. Result of the four-point test shows that increasing the thickness of profiles steel sheet gives major effect to the deflection and ultimate load. The deflection and ultimate load of 1.0mm thick panel specimen is 16.45% and 34.45% respectively. Therefore, increased the thickness of profiled steel sheet can enhance the stiffness and strength of the lightweight composite slab systems. It also found that the infill material used in these experimental gives minor effect to deflection and ultimate load. The deflection and ultimate load of panel specimen with foamed concrete is 21.18% and 16.66% respectively. Thus, foamed concrete can be used only for non-structural purposed only such as sound proofing and fire resistance.

Seismic Performance of Multistorey RC Frame With Various Masonary Infill Bricks

Brick is the most commonly used material for building construction. In India it is common use to construct reinforced concrete buildings with unreinforced infill. Infill panels have been made of heavy rigid materials such as red bricks or concrete blocks. Now in India , infill materials such as light weight bricks (AAC) or hollow blocks are to be used as masonry infill material in RC buildings. On the performance of RC buildings, it has been recognized that infill materials have significant effect. This research work on comparison of seismic analysis and design of G+12 building using AAC (Autoclaved aerated concrete block ) and conventional bricks were analysed by under Time history analysis. Infill materials has been accepted influence the seismic performance considerably influence the in filled framed structures. Number of researchers were studied the behaviour of in filled RC frames analytically. Most of the research work carried out , paying attention on parameters such as the variation of distribution of masonry infill and the stiffness of frame elements.. Modelling of the structure is done by Etabs software. Lateral seismic force RC frame is carried out by using equivalent static method as per IS 1893(part 1) : 2002 for earthquake. In the present study is made to study the behavior of RC frame structure using conventional bricks, and light weight bricks (AAC) infill. The various results such as storey acceleration, storey displacement, storey drift, storey stiffness are compared to know the suitable infill material in seismic prone zones.

Behaviour of Polymer Filled Composites for Novel Polymer Railway Sleepers

A novel concept of polymer railway sleeper is proposed in this study that has the potential to meet static performance requirements within the cost of hardwood timber. The existing challenges of composite sleepers, such as low performance or high cost, can be overcome using this innovative concept. Such a proclamation is proven through limit state design criteria and a series of experimentations. Results show that polyurethane foam as an infill material can provide sufficient strength and stiffness properties to the sleeper, but the inadequate screw holding capacity could be a problem. This limitation, however, can be overcome using a particulate filled resin system. The findings of this study will help the railway industry to develop a timber replacement sleeper.

An innovative tubular standing support incorporating PVC and FRP composites: laboratory tests

With the depletion of shallow resources, the drawbacks of conventional bolting system in sustaining the integrity of the roadway have drawn much attention. Developing the innovative secondary standing support is therefore to be urgent. This paper presents a hybrid tubular standing support, which consists of an exterior container made of PVC and fibre-reinforced polymer (FRP) composites and the infill material made of coal rejects and high flowable cementitious grout material. Compared with other marketable standing support, the combination application of the large rupture strain PVC tube and the FRP composite with high strength-to-weight ratio can provide the effective confinement to infill material, which may result in the strain hardening behaviour. The use of coal reject to generate the backfill material is believed to be effective and thus is attractive from the design aspect. To verify these mentioned advantages, a series of compression tests were conducted on this FRP-PVC tubular standing support (FPTSS) with different thickness of the FRP jacket. In addition, the compression tests were also conducted to investigate the compressive behaviour of FRP tubular standing support (FTSS) and PVC tubular standing support (PTSS). Test results indicated that the combination of FRP and PVC composite achieve the superior behaviour either in terms of the compressive strength or the deformation ability.

The Nature of Infill Material on the Discontinuities of the Muntele Mare Granite (Beliş-Fantânele, Romania)

The stability of rock massifs is strongly influenced by natural degradation processes. In combination with hydrothermal activity or atmospheric exposure, rock alteration processes can lead to the formation of secondary phases that ultimately control the rock quality and slope stability, which are particularly important for engineering works (e.g., road cuts, open pits, quarries, tunnels). The Bozgai open quarry in the Muntele Mare granite massif in the northern Apuseni Mountains (Romania) offers an excellent opportunity to investigate the influence of alteration processes on rock properties, especially owing to the extensive exposure of granite and specific mineral assemblages of hydrothermal genesis to atmospheric conditions. The alteration processes generated secondary phases located on the primary minerals of the affected rocks or deposited as infill material along the granite discontinuities. Natural and oriented samples of the Bozgai quarry infill material were investigated using polarized light, X-ray diffraction, and scanning electron microscopy to obtain images and identify their mineralogical composition. The hydrothermal vein material consists of kaolinite, illite, pyrite, marcasite, quartz, iron hydroxides, albite, and microcline. These samples were exposed to atmospheric oxygen and meteoric water and secondary sulphates (jarosite and gypsum) formed in an acidic environment generated by the oxidization of pyrite and marcasite. The sheeted structure of kaolinite and geochemical behavior of the sulphates in the presence of water play a particularly important role in the reduced rock slope stability in the Bozgai quarry.