Applied Mechanics and Materials Vol. 777

Abstract: By pull-out tests between GFRP bolts and concrete, the influence of the diameter and surface shape of GFRP bolts on the bonding performance was studied. By ANSYS analysis, the effects of anchorage length, diameter, geotechnical parameters and prestress on the bonding performance were studied. The experimental and numerical analysis results show that: with the increase of bolt diameter, the bonding strength of bolts decrease and the slippages increase. The bigger the parameters of rock-soil like modulus of elasticity, cohesion strength and internal friction angle are, the better is the bond behavior and the smaller is the slippage. The prestress plays an important role in the rock stability and the restriction of deformation. With the enhancement of the prestress of bolts, the peak shear stress increases but the effective anchorage length nearly stays the same.

Abstract: This research selected Z-shaped section column joints in RC frame as the investigating object and considered the mechanical parameters extracted from physical model test results, proposed the finite element model of concrete damaged plasticity. Combining concrete damage plasticity model parameters on ABAQUS of concrete constitutive relationship from appendix C of Code for design of concrete structures (GB50010-2010), add the concept of damage factor to Energy equivalence principle, construct finite element model of Z-shaped column joints in RC frame, and simulated the test process under horizontal cyclic loading. The analysis results indicate that the finite element model can perfectly simulate action. It can reflect the mechanical properties of Z-shaped column joints in frame under horizontal cyclic loading, which is proved correct and reliable.

Abstract: Significant number of reinforced concrete building frames executed in the ‘50’s-60’s in Europe need seismic upgrading. At those times understanding of earthquake effects was insufficient and quality control on construction sites lacking. This combination resulted in buildings framed in reinforced concrete with bad quality materials and inadequate reinforcement. The low-medium rise buildings often house public functions today. In this paper, we analyze the potentials and limitations of using light prefabricated steel wall systems (LGSW) to upgrade frames to higher seismic standard. Results show that r.c. frames with virtually no seismic resistance (PGA~0.05·g) can be upgraded to resist intermediate earthquakes, possibly up to PGA~0.2·g. The LGSW’s have remarkable flexibility to adapt to the refurbishment requirements in terms of stiffness and strength, and also provide adequate ductility.

Abstract: This paper studied the cracking and sliding working performance of modified mortar isolation sliding layer in a sliding isolation technique suitable for the rural construction. The technology realizes the sliding isolation by setting the up and down ring beams at the outdoor ground bonded by low-grade modified mortar and the shear deformation limit by setting rubber beams. Through the compression-shear tests on different grades of modified mortar which mixed with graphite and talc, the horizontal shear strength of different modified mortars have been acquired. the friction performances of different modified mortars have been Compared by the friction coefficient tests,. Through calculating, the sliding performances of modified mortar layer under the seismic actions of different seismic fortification intensities have been achieved. The research shows that the modified mortar sliding layer has well sliding performance, and it is able to meet the demand of sliding isolation of the rural construction.

Abstract: In order to learn seismic behavior of partially encased concrete composite columns, experimental study on five H steel partially encased concrete composite columns was carried out under low cyclic loading. The main parameters were the axial compression ratio, steel ratio, shear span ratio. The test results show that deformation ability decreases as axial compression ratio increases; and as steel ratio increases, horizontal bearing capacity and deformation ability increases.

Abstract: Test & research on the shearing strength of the hollow mortar-less fabricated concrete block & masonry has been done in this article. A proposed formula has been put forward in this article by analyzing the influence of the shear loading methods on the shearing strength using the shearing test data of 27 standard test specimens’ continuous seams divided into 9 groups with 100% concrete infill ratio.

Abstract: The shapes of concrete hollow block for building wall in recent years have been investigated and analyzed in the paper. Firstly, a standard to evaluate the shapes of concrete hollow block is recommended. Secondly, a simple and clear method of graph is adopted to classify the shapes, and numerical of typical shapes are illustrated and evaluated by the standard recommended. At last, problems of concrete hollow block in China were summarized and raised.

Abstract: Cracks in the floor slab is a common problem and should be paid great attention in construction. In this paper, combining with an example, the cause of cracks in cast-in-place concrete slabs has been analyzed, then proposed control measures of cast-in-place floor crack.The control measures has a certain reference value for management and quality control of concrete construction work.

Abstract: Corrosion of steel bars has become the primary cause for the concrete durability problem. Stress concentration due to uneven corrosion affect the mechanical properties of reinforced bar. This paper take HRB400 rebar for example to analyze the effect. FEM is conducted to analyze the effect of corrosion pit position on yield strength and ultimate strength. The result shows that corrosion pit in transverse rib has a different effect on yield strength and ultimate strength, while corrosion pit in longitudinal rib and reinforced column make yield strength and ultimate strength of reinforced bar decrease in varying degrees.

Abstract: The main chemical composition of waste brick is silicon dioxide,by means of chemical can stimulate its activity.In this experiment, gypsum, lime sodium hydroxide as activators,through the testing and research about the properties of compressive strength, dry density, water absorption of brick powder foam concrete,analyse the influence of three activators on the properties of foam concrete.The test results show that the:Mixing about 25% lime can guarantee the dry apparent density on the basis of compressive strength increases;Mixing 20% gypsum can make the strength and dry apparent density relatively stable;The incorporation of NaOH make the foam concrete appear quick setting,so it should not be used alone as activator.