Frame property of unequal storey height with specially shaped columns under cyclic loading

A 1/3-scale reinfored concrete(RC) frame of unequal storey height with specially shaped columns was tested under low frequency cyclic loading.The damage characteristic,bearing capacity,deformation capacity and ductility were analyzed.The restoring force model of the frame was obtained based on the study of the hysteresis curve measured in experiment,and the stiffness degeneration characteristics of every storey of the frame were analyzed.Finally the accumulated damage was analyzed with the damage assessment model.It is shown that the seismic behavior of this frame of unequal storey height with specially shaped columns is generally good,but the bottom of first floor column is a weak part,which should be paid more attention in design,and the restoring force model derived from this experiment can be seen as a valuable guide for design and non-linear finite element analysis for this kind of structure.

Seismic Behavior of Specially Shaped Column Joints with X-Shaped Reinforcement

To investigate the seismic behavior of specially shaped column joints with X-shaped reinforcement,two groups of specimens with or without X-shaped reinforcement in joint core region were tested under constant axial compression load and low reversed cyclic loading,which imitated low to moderate earthquake force.The seismic behavior of specially shaped column joints with X-shaped reinforcement in terms of bearing capacity,displacement,ductility,hysteretic curve,stiffness degradation and energy dissipation was studied and compared to that without Xshaped reinforcement in joint core region.With the damage estimation model,the accumulated damage was analyzed.The shearing capacity formula of specially shaped column joints reinforced by X-shaped reinforcement was proposed with a simple form.The test results show that X-shaped reinforcement is an effective measure for improving the seismic behavior of specially shaped column joints including deformation behavior,ductility and hysteretic characteristic.All specimens were damaged with gradual stiffness degeneration.In addition,X-shaped reinforcement in the joint core region is an effective way to lighten the degree of cumulated damage.The good seismic performance obtained from the specially shaped column joint with X-shaped reinforcement can be used in engineering applications.The test value is higher than the calculated value,which indicates that the formula is safe for the design of specially shaped column joints.

Conformal mapping modeling of metal plastic deformation and die cavity in special-shaped extrusion

With the help of Complex Function Mapping studied results, the analysis function of Conformal Mapping is set up. Since the complicated three dimension’s deformation problems are transferred into two dimension problems, both the stream function and strain ratio field are analyzed in the metal plastic deformation. Using the upper-bound principles, the theory of metal deformation and die cavity optimized modeling is established for random special-shaped product extrusion. As a result, this enables the realization of intelligent technique target in the die cavity of CAD/CAM integration.

Hysteretic behavior of special shaped columns composed of steel and reinforced concrete(SRC)

This paper describes a series of experimental investigations on seventeen specimens of steel reinforced concrete special shaped(SRCSS) columns under low cyclic reversed loading using parallel crosshead equipment. Nine T-shaped SRC columns, four L-shaped SRC columns and four +-shaped SRC columns were tested to examine the effects of shape steel confi guration, loading angle, axial compressive ratio and shear-span ratio on the behavior(strength, stiffness, energy dissipation, ductility, etc.) of SRCSS column specimens. The failure modes and hysteretic performance of all the specimens were obtained in the tests. Test results demonstrate that the shear-span ratio is the main parameter affecting the failure modes of SRCSS columns. The specimens with small shear-span ratio are prone to shear failure, and the primary failure planes in SRCSS columns are parallel to the loading direction. As a result, there is a symmetry between positive and negative loading directions in the hysteretic curves of the SRCSS columns. The majority of displacement ductility coeffi cients for all the specimens are over 3.0, so that the SRCSS columns demonstrate a better deformation capacity. In addition, the equivalent viscous damping coeffi cients of all the specimens are greater than 0.2, indicating that the seismic behavior of SRCSS columns is adequate. Finally, the superposition theory was used to calculate the limits of axial compressive ratio for the specimens, and it is found that the test axial compressive ratio is close to or smaller than the calculated axial compressive ratio limit.

Improved design of special boundary elements for T-shaped reinforced concrete walls

This study examines the design provisions of the Chinese GB 50011-2010 code for seismic design of buildings for the special boundary elements of T-shaped reinforced concrete walls and proposes an improved design method. Comparison of the design provisions of the GB 50011-2010 code and those of the American code ACI 318-14 indicates a possible deficiency in the T-shaped wall design provisions in GB 50011-2010. A case study of a typical T-shaped wall designed in accordance with GB 50011-2010 also indicates the insufficient extent of the boundary element at the non-flange end and overly conservative design of the flange end boundary element. Improved designs for special boundary elements ofT-shaped walls are developed using a displacement-based method. The proposed design formulas produce a longer boundary element at the non-flange end and a shorter boundary element at the flange end, relative to those of the GB 50011-2010 provisions. Extensive numerical analysis indicates that T-shaped walls designed using the proposed formulas develop inelastic drift of 0.01 for both cases of the flange in compression and in tension.

Interfacial stress transfer behavior in a specially-shaped fiber/matrix pullout test

Specially designed fibers are widely used in engineering practice because the specially-designed shape can help to improve the bonding strength of the fiber and the interface. Studied in this paper is the interfacial shear stress transfer behavior on both sides of the specially designed fiber when it is being pulled out; in which automatic analysis of three-dimensional photoelasticity is employed and the finite element method is adopted. The results show that the stress transfer occurs mainly in the region near the fiber＇s embedded end where the stress reaches its critical point, leading to debonding of the interface. Before debonding, as the pullout loading increases, the peak value of shear stress transfers along the fiber from the embedded end to the interior of the matrix, and then stops at the hooked part of the fiber because of its impediment. When the interface begins to debond as the load increases, the shear stress can be transferred to the hooked part.

Integration Mechanism of Ideological and Political Education with Specialized Knowledge in the Course of Green Building Design

This paper aims to explore the integration of ideological and political education with specialized knowledge in the course of green building design.Through an analysis of the green building design course,combined with the current social development background and the need for ecological and environmental protection,the study investigates how to effectively integrate ideological and political education elements into course instruction to enhance the comprehensive quality and green design capabilities of architecture students.The paper analyzes the content and characteristics of the green building design course and proposes an integration mechanism for ideological and political education in green building design teaching,aiming to cultivate architecture talents with green design concepts and good ideological and political qualities.

Special Space and Plant Landscape Design of Urban Ecological Buildings

This paper mainly discusses the application of plant landscape design in special space of ecological buildings. From the concept of special space of ecological buildings,it elaborates social benefits and ecological benefits of greening projects in special space. It introduces the classification method for special space of ecological building with habitat as the major part combining characteristics of building form. On the basis of such classification,it discusses green design method and plant selection principle,to provide certain reference for garden designers in green design of ecological buildings.

Plant Landscape Design in Special Space of Ecological Buildings

This paper mainly discussed the application of plant landscape design in special space of ecological buildings. From the concept of special space of ecological buildings,it elaborated social and ecological benefits of greening projects in special space. It proposed the classification method for special space of ecological building with habitat as the major part and combined with characteristics of building form. On the basis of such classification,it discussed green design method and plant selection principle,in the hope of providing certain reference for garden designers in green design of ecological buildings.

Copper-organic Framework Constructed from Rod-shaped Secondary Building Units with Selective Sorption Property

One novel metal-organic framework [Cu2（L）（μ3-OH）]n（1, H3L = [1,1＇：3＇,1＇＇-terphenyl]-4,4＇＇,5＇-tricarboxylic acid） has been synthesized and characterized by single-crystal powder X-ray diffraction, IR and thermogravimetric analyses. Complex 1 crystallizes in orthorhombic crystal system, space group Pbca with a = 21.573（19）, b = 5.404（5）, c = 33.78（3） ？, C21H（12）O7Cu2, Mr = 503.39, V = 3938（6） A^3, Z = 8, Dc = 1.698 g·cm^-3, μ = 2.202 mm^-1, F（000） = 2016, 1.531〈θ〈25.009°, λ（Mo Kα） = 0.71073 A, T = 293（2） K, the final R = 0.0448 and wR = 0.1002. The structure of complex 1 is a three-dimensional（3D） framework based on infinite rod-shaped secondary building units and can be simplified as kgd topology. The gas adsorption measurements for N2, CO2, H2O, CH3OH and CH3CH2OH have been done. Fortunately, the selective sorption of CO2 over N2 was found at 195 K.

Editorial: Special subject on the mechanical behavior of fire dynamics in high-rise buildings

With rapid economic and social development in China, high-rise buildings have continuously sprung up since 2006. However, several big fire accidents in high-rise buildings such as the Beijing Television Cultural Center fire in 2009 and the Shanghai Jing＇an District fire in 2010 etc. have claimed people＇s lives and caused huge amounts of economic and property losses,

Similar extrusion and mapping optimization of die cavity modeling for special-shaped products

Aimed at the modeling issues in design and quick processing of extruding die for special-shaped products, with the help of Conformal Mapping theory, Conformal Mapping function is determined by the given method of numerical trigonometric interpolation. Three-dimensional forming problems are transformed into two-dimensional problems, and mathematical model of die cavity surface is established based on different kinds of vertical curve, as well as the mathematical model of plastic flow in extruding deformation of special-shaped products gets completed. By upper bound method, both vertical curves of die cavity and its parameters are optimized. Combining the optimized model with the latest NC technology, NC Program of die cavity and its CAM can be realized. Taking the similar extrusion of square-shaped products with arc radius as instance, both metal plastic similar extrusion and die cavity optimization are carried out.

Experimental Study on Seismic Behavior of Exterior Joints of Special-shaped Columns with Different Lengths of Limbs

Four exterior joints with special-shaped columns which have different lengths of limbs are tested under low cyclic loading. Speeial-shaped columns adopted are L- and T-shaped in section. It can be concluded that crack pattern, failure mode and shear strength of joints are affected by the length of limb, and that shear strength and ductility increase with the length of limb; the joints with the flexural failure of the beam have better seismic behavior than those with the shear failure of the joint core.

Tall Buildings with Dynamic Facade Under Winds

Burgeoning growth of tall buildings in urban areas around the world is placing new demands on their performance under winds.This involves selection of the building form that minimizes wind loads and structural topologies that efficiently transfer loads.Current practice is to search for optimal shapes,but this limits buildings with static or fixed form.Aerodynamic shape tailoring that consists of modifying the external form of the building has shown great promise in reducing wind loads and associated structural motions as reflected in the design of Taipei 101 and Burj Khalifa.In these buildings,corner modifications of the cross-section and tapering along the height are introduced.An appealing alternative is to design a building that can adapt its form to the changing complex wind environment in urban areas with clusters of tall buildings,i.e.,by implementing a dynamic facade.To leap beyond the static shape optimization,autonomous dynamic morphing of the building shape is advanced in this study,which is implemented through a cyber–physical system that fuses together sensing,computing,actuating,and engineering informatics.This approach will permit a building to intelligently morph its profile to minimize the source of dynamic wind load excitation,and holds the promise of revolutionizing tall buildings from conventional static to dynamic facades by taking advantage of the burgeoning advances in computational design.

Seismic performance of a reinforced concrete building retrofitted with self-centering shape memory alloy braces

Self-centering earthquake-resistant structures have received increased attention due to their ability to reduce post-earthquake residual deformations and,thus,repair time and cost.This stimulated the development of recentering shape memory alloy(SMA)dampers that use superelastic nitinol wires to dissipate energy and self-center the structure.However,there are still a few case studies applications on full-scale RC buildings in the literature.Moreover,general guidelines or even simplified approaches for the practical design of SMA damped braces are still lacking.This paper focuses on evaluating the effect of using self-centering shape memory alloy dampers for buckling-restrained braces applied for the seismic retrofit of a complex RC building structure.A design method originally proposed for elastoplastic dampers was implemented to size the SMA dampers to be placed on selected spans and stories of a building.The effectiveness of the design procedure was demonstrated by nonlinear time-history analyses under different sets of earthquake strong ground motions.The analysis results show that the recentering shape memory alloy bracing system is effective in limiting the maximum transient inter-story drifts and reducing the residual inter-story drifts after strong seismic events,due to its excellent recentering behavior together with its not negligible energy dissipation capacity.

Designing with Building Bricks and Shape Grammar

This paper correlates the use of building blocks with the shape grammar theory in the design process. The main goal is to present the potentialities of the various building blocks, which combined with Shape grammar can contribute to the creative process, particularly for the formal composition in the field of Architecture, Urbanism and Design. The methodology is based on a literature review and reflections derived from the observations of the use of the building blocks during experiments carried out in the scope of research with students of the undergraduate course in Architecture and Urbanism. Starting from the discussions proposed by George Stiny on design with Froebel’s buildings gifts and from experiments with other building blocks, such as Archbricks, it is found that building blocks have their own vocabulary and rules, which can be appropriated and exploited by designers in the construction of new shape grammars.

Calibration of split Hopkinson pressure bar system with special shape striker

In order to present basic guidance for system calibration of split Hopkinson pressure bar(SHPB) with the special shape striker,wave characteristics and dynamic responses of SHPB under striker impact were analyzed.Stress generated by the special shape striker tends to have a half-sine waveform and has little wave dispersion during its propagation.Impact velocities of the special shape striker and peak values of generated stress still have linear relation but with a different coefficient from that of cylindrical strikers.From stress histories on the surfaces of the input bar impacted by the special shape striker off-axially and obliquely,it is found that the misalignment impacts usually trigger wave distortion and amplitude decrease,which can be used to identify the poor system adjustment.Finally,the system calibration of SHPB with the special shape striker can be classified into four steps:system adjustment,wave distortion identification,measurement calibration and transmission calibration,where the measurement calibration factor and transmission calibration factor are elaborated and redefined.

Exact solution of free vibration of adjacent buildings interconnected by visco-elastic dampers

With consideration of a high-rise coupled building system,a flexible beams-based analytical model is setup to characterize the dynamic behavior of the system.The general motion equation for the two beams interconnected by multiple viscous/visco-elastic dampers is rewritten into a non-dimensional form to identify the minimal set of parameters governing the dynamic characteristics.The corresponding exact solution suitable for arbitrary boundary conditions is presented.Furthermore,the methodology for computing the coefficients of the modal shape function is proposed.As an example,the explicit expression of the modal shape function is derived,provided only one damper is adopted to connect the adjacent buildings.Finally,to validate the proposed methodologies,three case studies are performed,in which the existence of the overdamping and the optimal damping coefficient are revealed.In the case of using one damper in connecting two similar buildings,the estimating equations for the first modal damping ratio are formulated.

Preparation and Properties of Paraffin/PMMA Shape-stabilized Phase Change Material for Building Thermal Energy Storage

The composite phase change material(PCM) consisting of phase change paraffin(PCP) and polymethyl methacrylate(PMMA) was prepared as a novel type of shape-stabilized PCM for building energy conservation through the method of bulk polymerization. The chemical structure, morphology, phase change temperature and enthalpy, and mechanical properties of the composite PCM were studied to evaluate the encapsulation effect of PMMA on PCP and determine the optimal composition proportion. FTIR and SEM results revealed that PCP was physically immobilized in the PMMA so that its leakage from the composite was prevented. Based on the thermo-physical and mechanical properties investigations, the optimal mass fraction of PCP in the composite was determined as 70%. The phase change temperature of the composite was close to that of PCP, and its latent heat was equivalent to the calculated value according to the mass fraction of PCP in the composite. For estimating the usability in practical engineering, thermal stability, reliability and temperature regulation performance of the composite were also researched by TG analysis, thermal cycling treatments and heating-cooling test. The results indicated that PCP/PMMA composite PCM behaved good thermal stability depending on the PMMA protection and its latent heat degraded little after 500 thermal cycling. Temperature regulation performance of the composite before and after thermal cycling was both noticeable due to its latent heat absorption and release in the temperature variation processes. The PCP/PMMA phase change plate was fabricated and applied as thermal insulator in miniature concrete box to estimate its temperature regulation effect under the simulated environmental condition. It can be concluded that this kind of PCP/PMMA shape-stabilized PCM with the advantages of no leakage, suitable phase change temperature and enthalpy, good thermal stability and reliability, and effective temperature regulation performance have much potential for thermal energy storage in building energy conservation.