Dai Guo Chen

Experiment Research on Thermal Performance of Foam Concrete Wall

Foam concrete is a new building energy-saving material, which has the characteristics of light weight, heat insulation and fire prevention. The use of foam concrete slab with grooves cast roof or wall as a template can reduce the amount of the construction process, the cost of project and improve the structural thermal insulation properties. By testing the thermal defects and heat transfer performance of outer insulation and self-insulated wall, and analysis 2 kinds of wall’s heat transfer coefficient, thermal inertia indicators and technical and economic characteristics with Building Heat Transfer Theory, obtain : Foam concrete self thermal insulation wall indoor a hot environment, thermal stability and resistance against external temperature fluctuations is stronger; foam concrete self thermal insulation wall have a good heat transfer performance, and have better marketing prospects.

Research on the Seismic of a Large Span Roof

By calculating a large span roof structures, get the intrinsic mode and real-time response of the structural under earthquake. The results showed that, the vertical acceleration response of structure is smaller than the horizontal acceleration response under EL-Centro wave and Tangshan wave. The vertical acceleration response is greater than the horizontal acceleration response under Lanzhou wave. The vertical displacement response of structure is greater than the horizontal displacement response under earthquake. Roof Destructed before the steel skeleton damage.

Numerical Simulation on the Overall Dynamic Response of One High-Rise Steel Frame

Using the finite element analysis software ANSYS to analyze the overall dynamic response of one specific high-rise steel-frame,including modal analysis, spectrum analysis and time-history analysis. Then do a comparative analysis with the results of calculation by the professional software PKPM. As the results: the structural calculation can use layer model; Larger mutations appeared in the stress of weak-story and the relevant story need to reinforce or set up supports under the anti-seismic design in the elastic time-history analysis of structure; Y-direction translation is preferentially happened in first order modal shape and lateral-torsional coupling happened in third order modal shape among the vibration mode analysis; The response spectrum analysis of frequent earthquake show that seismic action is more serious in ground layer.

Experimental Study of the Tensile Bond Strength in Concrete Aggregate - Paste Interfacial Transition Zone

Study on the characteristics of tensile bond strength in concrete interfacial transition zone. Calculate the tensile bond strength of interfacial transition zone in concrete by the way of vertical drawing cobblestones of different grain size from C30 concrete by MTS hydraulic loading system .(the grain size include 50,70,90,100mm) results show that:1.when the cobblestones diameter is in a certain range(<90mm in this experiment)or the bonded area is in a certain range(<5251 mm2 in this experiment), The tensile bond strength of concrete interfacial transition zone nothing to do with the cobblestones diameter and the bonding area.2.If the cobblestones diameter or the bonded area is too large, it will affect the bonding effect of the cobblestones and concrete, and cause the depression of tensile bond strength, Therefore , In the actual engineering we should avoid the use of large diameter cobblestones .3. The tensile bond strength of C30concrete interfacial transition zone is approximately 4% - 10% of compressive strength of concrete.

Numerical Simulation on Beam-Column Joint in the Added-Layers Steel Structure under Monotonic Loading

Add layers for low-rise steel structure building can improve its using function. Use ANSYS analyze three added-layers beam-column joints of steel structure under the Monotonic loading. The results showed that: the joint reinforced by angles belongs to semi-rigid joint. Considering the construction and Structural requirements, the performance of this type joint is the most economical of all. The three joints all experience fully elastic deformation before them destructed, although the joint with only weld is deformation and failure, and the joint reinforced by haunched slab have larger deformability to resistance the plastic deformation, ultimate bearing capacity and initial stiffness, is one of the most conservative way of the joint’s reinforcement.

Study on Steel Strand’s Reasonable Tension Order of Reaction Wall

Pre-stressed reaction wall is an important test facility in structure laboratory．Reaction wall will bear large static and dynamic loads when working, so pre-stressed concrete structure is often used. A model of micro-concrete pre-stressed reaction wall is made in the test in order to insure tension quality of steel strand of reaction wall. Proposed 4 different tension schemes of reaction wall pre-stress rebar, and a comparative study on the variety trend and distribution of strain on reaction wall in the 4 different schemes．The experimental results show that the best schemes of tension pre-stress rebar is：use the wall cross-section center of gravity as the symmetric point, tension symmetrical up and down from central to outside．And we suggest that two times or supplement tension methods be use to stretching steel strand of reaction wall.

Research on Mechanical Behavior of Reinforced RC Beams Strengthened with Anti-Arch Method

We analyze the mechanical property of strengthening RC beam by using the method of arch pasting with carbon fiber and directly pasting CFRP through numerical simulation and model test. It explains that strengthening RC girder by using the method of arch can solve the influence of beams loading by the second time which exists in the method of pasting CFRP in strengthening reinforced concrete beams and it can improve the girders load when it cracks and the carrying capacity; decreasing the deflection deformation and crack width and gap when the girder carries load; It can make the most use of the character of carbon fibers high strength. The results play very important role of guiding to engineering.

Seismic Damage Analysis and Reinforcement Measures Research of a Long-Span Structure

Abstract: Taking a Practical Big Span Stadium Project as the Background, in View of its Particularity that it Suffered Earthquake Damage and Fortification Intensity Increased after Earthquake, through the Field Detection and Finite Element Model to Analyze Earthquake Damage of Structure Caused by Wenchuan Earthquake, and Research the Feasibility of Seismic Strengthening with Hadas on the Structure Whose Fortification Intensity Increased after Earthquake. the Results Show that: 1) the Big Span Structure Severely Damage by the Earthquake, the Second Layer Is Relatively Weak Layer, Prone to Local Damage and Affect Whole Anti-seismic Performance of Structure, 2) Hadas Can Increase the Initial Stiffness and Effectively Reduce the Structure Seismic Response, Has Better Effect on Overall Reinforcement, 3) it Is Reasonable to Improve the Seismic Fortification Intensity of this Region.

Simulation Calculation Analysis of RC Beam Strengthened with Carbon-Fiber by Reverse-Arch Method

Using utilities equipment to make the reinforced concrete girder to generate a kind of reverse-arch radian, then paste CFRP on the under-part of the girder, after the CFRP was maintained, unload, at this time, the CFRP is working together with the primary reinforced concrete girder. Using analysis software ANSYS to simulate this process, comparing with the RC beam strengthened with carbon-fiber directed, a conclusion was got that is the deflection of a RC beam strengthened with carbon-fiber by reverse-arch method is much smaller and the CFRP to bear much loads than the ordinary method. The conclusion can be a reference to the similar projects.

Experimental Study on Dynamic Characteristics of Sandy Pebble Soil

Through the laboratory dynamic triaxial test of sandy pebble soil, evolution law of influence of confining pressure and vibration frequency on dynamic strength is analyzed. Analysis indicates that dynamic stress of sandy pebble soil improves in a large degree with accretion of vibration frequency, dynamic strength of which increases significantly with confining pressure rising, and relation of dynamic stress and dynamic strain can also be symbolized with the R.L.Kondner hyperbola curve. Meanwhile, dynamic elastic modulus of sandy pebble soil decreases with growth of dynamic strain, while increases with growth of consolidation pressure.