皇城根为啥叫成黄城根

北京故宫的宫墙外,还有一道皇城。皇城外侧的一带,人们就管它叫“皇城根”。可是,以后建成马路,就叫成“黄城根”,这一字之改,出于何故?皇城建于明永乐年间(1406—1420年)。明朝重建北京城时,先建宫室、紫禁城,再建皇城和都城,以后嘉靖时加筑外城,因财力短缺,只建了南边,老北京城共有四道城墙,平面成“凸”字形。

楼板上砌筑隔墙的可能性分析

长期以来,人们对能否在楼板上直接砌筑隔墙始终持怀疑态度,按现行计算方法,楼板重量、隔墙砌体重和楼板上的使用荷载均由楼板承受,其总和已超过楼板的承载能力.造成楼板的挠度和裂缝超过容许值。因此,目前大量的设计都采用在墙下设置隔墙梁来承受墙体荷载,这样给建筑物的施工、使用都带来了很多不便,而在另一方面,目前确有个别建设工程采用了直接砌筑隔墙于楼板上的作法,若按常规方法计算存在问题。

Seismic performance evaluation of steel frame-steel plate shear walls system based on the capacity spectrum method

This paper presents some methods that the standard acceleration design response spectra derived from the present China code for seismic design of buildings are transformed into the seismic demand spectra, and that the base shear force-roof displacement curve of structure is converted to the capacity spectrum of an equivalent single-degree-of-freedom （SDOF） system. The capacity spectrum method （CSM） is programmed by means of MATLABT.0 computer language. A dual lateral force resisting system of 10-story steel frame-steel plate shear walls （SPSW） is designed according to the corresponding China design codes. The base shear force-roof displacement curve of structure subjected to the monotonic increasing lateral inverse triangular load is obtained by applying the equivalent strip model to stimulate SPSW and by using the finite element analysis software SAP2000 to make Pushover analysis. The seismic performance of this dual system subjected to three different conditions, i.e. the 8-intensity frequently occurred earthquake, fortification earthquake and seldom occurred earthquake, is evaluated by CSM program. The excessive safety of steel frame-SPSW system designed according to the present China design codes is pointed out and a new design method is suggested.

Strain coordination of quasi-plane-hypothesis for reinforced concrete beam strengthened by epoxy-bonded glass fiber reinforced plastic plate

The testing of thirteen reinforeed concrete （RC） beams strengthened by epoxy-bonded glass fiber reinforced plastic plate （GFRP） shows that the RC beam and the GFRP plate with epoxy bonding on it can work fairly well in coordination to eaeh other. But there is relative slipping between RC beam and GFRP plate. And the strain of GFRP and steel rebar of RC beam satisfies the quasi-plane-hypothesis, that is, the strain of longitudinal fiher that parallels to the neutral axis of plated beam within the scope of effective height （ h0 ） of the cross section is in direct proportion to the distance from the fiber to the neutral axis. The strain of GFRP and steel rebar satisfies the equation： εGFRP=Kεsteel.

Effect of boundary conditions and convection on thermally induced motion of beams subjected to internal heating

Numerical exercises are presented on the thermally induced motion of internally heated beams under various heat transfer and structural boundary conditions. The dynamic displacement and dynamic thermal moment of the beam are analyzed taking into consideration that the temperature gradient is independent as well as dependent on the beam displacement. The effect of length to thickness ratio of the beam on the thermally induced vibration is also investigated. The type of boundary conditions has its influence on the magnitude of dynamic displacement and dynamic thermal moment. A sustained thermally induced motion is observed with progress of time when the temperature gradient being evaluated is dependent on the forced convection generated due to beam motion. A finite element method (FEM) is used to solve the structural equation of motion as well as the heat transfer equation.

FRP Retrofitted RC Slabs Using Finite Difference Model

Current guidelines recommend using single-degree-of-freedom(SDOF) method for dynamic analysis of reinforced concretec (RC) structures against blast loads, which is not suitable for retrofitted members. Thus, a finite difference procedure developed in another study was used to accurately and efficiently analyze the dynamic response of fibre reinforced polymer (FRP) plated members under blast loads. It can accommodate changes in the mechanical properties of a member's cross section along its length and through its depth in each time step, making it possible to directly incorporate both strain rate effects (which will vary along the length and depth of a member) and non-uniform member loading to solve the partial differential equation of motion. The accuracy of the proposed method was validated in part using data from field blast testing. The finite difference procedure is implemented easily and enables accurate predictions of FRP-plated-member response.

Performance Comparison and Analysis of Heating and Ventilation of Two Kinds of Roof Solar Collectors

Two roof solar collectors (RSCs), conventional single pass RSC and new double pass RSC, were compared. The new roof solar collector, which is formed by integrating a double pass solar air collector with the roof of the building, can be operated more efficiently for space heating in winter, and for natural ventilation in other seasons. To evaluate the performances of the two RSCs for both space heating and natural ventilation, a single traditional Chinese style house, on which the two RSCs will be mounted, was developed. The efficiency of solar energy conversion for the new RSC is higher than that of the single pass one by 10% on average, and the ventilation rate contributed by natural ventilation for the new RSC can be improved to a great extent for most cases, indicating that the new RSC is superior to the single pass one from the viewpoint of both space heating and natural ventilation. The new RSC is more potential for improving indoor thermal environment and energy saving of buildings.

Reinforcement Efficiency Analysis of Geosynthetic-Reinforced Embankment with Different Soil Properties

Based on finite element （FE） method, an analysis program of geosynthetic-reinforcement embankments （GRE） is propesed. The improvement of stress field of surface layer of GRE after reinforcement can be indicated by this program. The comparison of failure area ratio of foundation soil before and after reinforcement is made, so that the efficiency of geosynthetic reinforcement under different soft soil properties can be shown. The embankment soil is simulated with Duncan-Chang model in this program, while reinforcement is modeled with linear elastic model and interface of reinforcement-soil by Goodman elements. Parameters about foundation soil, such as cohesion, inner friction angle and unit weight are considered, as well as three Duncan-Chang model parameters： modulus coefficient, bulk modulus coefficient and break ratio. The relationship between those soil parameters and failure area ratio indicate the reinforcement efficiency of GRE. The results show the cohesion and inner friction angle are the most important parameters for reducing the failure area, while modulus coefficient and bulk modulus coefficient, have little effect on the calculation results; the reinforcement efficiency is low if the cohesion and inner friction angle of foundation soil are too small or too big; different foundation soil will get different conclusions. The selection of model parameter is an important procedure for accurate modeling of GRE by numerical method.

Ornaments as Means of Efficient Reinforcement in Heritage Buildings

Heritage consists of those items people have inherited and want to keep, as they give them the sense of the past of their cultural identity, but these items, especially the buildings, could not face deteriorations during their period of life, such as the change of loads, the act of the environmental conditions, the effect of the duration time of the materials and the misuse of the occupants. They need special treatments and reinforcements to keep the structural state or to gain extra forces to receive the new loads. But the traditional ways of reinforcement do not prove endless solutions as the most means of the deteriorations from the nature. So, the liability issue is how to find the least reinforcement within the means of technology with the least deterioration and in a less time or by other ways efficiently. The hypothesis considers that the ornaments in some heritage buildings are found in critical levels of the construction which can share in an efficient way in the reinforcement processes of such buildings.

Dynamic Crowd Loading Test on Tibetan Ancient Structures

The field test of a typical Tibetan ancient structure instrumented with displacement and acceleration transducers was conducted to measure time histories due to crowd walking and running. The test case is introduced firstly. The displacement time histories are then used to analyze the dynamic property such as fundamental frequency of vertical vibration and damping ratio of the test structure, and the acceleration time histories are applied to evaluate the floor vibration serviceability. The floor interaction and comparison of human walking and running are also discussed. Some valuable conclusions are given.

Safety analysis of building foundations over old goaf under additional stress from building load and seismic actions

Additional displacement of the building foundations over old goaf are prone to happen under the addi- tional loads induced by new buildings, weakening-rock mass by mining and seismic actions, which will cause serious damage to the buildings. In order to analyze the safety of the building foundations safety over the old goaf. the structure characteristics of the strata over the old goaf was investigated and the instability conditions of overhanging rocks upon old goaf were also analyzed in this paper. The results indicate that the stability of overhanging rocks is remarkably decreased by the interactions of mining fractures, earthquake force and building load, in addition, the settlement of the foundations over old goal is increased by the instability of overhanging rocks. According to the location of a new power plant in Yima Mine and its ambient conditions, we defined the influence scope of old goal via resistivity tomography. Based on the seismic parameters of the construction site, a numerical FLAC3d model of the building foundation under the seismic actions and building load was developed. The numerical results are obtained as follows： the foundation of the main power house meets the requirement of 6° seismic fortification intensity： however, under 7° seismic fortification intensity, the maximum differential settlement of foundation between the neighboring pillars is close to the maximum allowable value, while the seismic fortification intensity reaches 8°, but the safety requirements will not be satisfied.

Assessing and Optimizing the Technical Life of Architectural Components of Low-Cost Multistoried Rental Housing in Jakarta

Low-cost multistoried rental housing （rumah susun sederhana sewa, abbreviated to rusunawa） recently has become the main policy for the Indonesian government to provide adequate housing for low income people in the metropolitan areas. In line with the policy, the government in the year 2005 has raised the technical life of building for low-cost multistoried rental housing from 30 years to 50 years. This study is conducted to assess variables that affect the technical life of architectural components, using Delphi study method involving stakeholders who have participated in the planning, design, construction, operation and maintenance of low-cost multistoried rental housing in Jakarta. Research findings contribute significantly to the assurance of technical life of architectural components in low-cost multistoried rental housing in Indonesia.

Evaluation of Common Delay Causes of Construction Projects in Singapore

The objectives of this paper were to identify and evaluating the common delay factors among owners, consultants and main contractors in building projects in Singapore. The interview and questionnaire method were used in this research. Randomly distributed questionnaire technique was applied to select samples of 74 various construction practitioners consisting of owners, consultants and main contractors to evaluat the severity of the 35 identified delay factors. The project investigated in this study included residential building and office building projects. The results found that delay in progress payment by owner, adverse weather conditions, main contractor financial problems, evaluation of completed works and act of god factor caused mostly severe delay in building construction project.

Reprocessing of Buildings＇ Demolition Waste and Utilization for the Manufacturing of New Products

Concrete is multicomponent composite material, consisting of coarse aggregate, fine aggregate, cement and water. Natural aggregates, as well as aggregates obtained after the reprocessing of buildings＇ demolition waste, can be used as coarse and fine aggregates. Characteristics of the hardened concrete depend on the raw materials, used for the preparation of concrete mixture, and their characteristics. The objective of the research is to analyse the sources of demolition waste, to describe the reprocessing technology of concrete waste, to investigate the production of the aggregate from the concrete waste, to analyse the main properties of these aggregates -- particles＇ density, bulk density, granulometric composition, hollowness and other properties, as well as to compare the obtained results with the requirements applicable to the aggregates based on natural materials.

Experimental Research on Seismic Performance of Storey-Adding Frame Structures

The seismic behaviors of an integral concreting frame, a light steel storey-adding frame and a storeyadding frame strengthened with carbon fiber reinforced polymer(CFRP)were investigated under low-cycle and repeated load(scale 1∶3). The failure characteristics, hysteretic behavior, rigidity degeneracy, deflection ductility and energy-dissipation capacity of the three specimens were compared. The test results reveal that chemicallybonded rebar technique can meet the requirements of storey-adding engineering. The carrying capacity, the deflection ductility, the energy-dissipating capacity and seismic performance of the light steel storey-adding frame are higher than those of the integral concreting frame, and they are the highest in the storey-adding frame strengthened with CFRP.

Community＇s Perceptions on Their Own Environment toward Disaster Mitigation and Prevention： A Case Study of Menteng Atas - Jakarta, Indonesia

Menteng Atas is a sub district （Kelurahan） in Southern Jakarta - Indonesia, under the district （Kecamatan） of Setiabudi. As a common crowded settlement in urban area, this location facing multi problems related to physical environment. Built environment with very high density and not well-arranged of fronts and position, also do not meet standards of healthy construction and environment are the main problems of Menteng Atas that brings to disasters such as flooding and fire. This paper explored how members of Menteng Atas community perceive their everyday surroundings within the context of an environment that has rapidly changed, primarily due to urban development. This paper also discuss how far they aware about their environment, the disasters prevention, and what they wants for the future of their environment. The study was start from the inside of the local community. Symbolic communication varies from one situation to the next were founded by studying the accounts, explanations, and social action that are meaningful to a group of people. This paper is trying to present and identify perception of host community on their own environment especially related to disasters prevention, and end up with some recommendations to achieve sustainable housing and settlement at this area.

Human Comfort Evaluation of a Steel-Concrete Composite Building Subjected to Aerobics

The current steel-concrete composite floors design might be susceptible to the resonance phenomenon, causing undesirable vibrations in the frequency range that is the most noticeable to humans, i.e., 4 Hz to 8 Hz. This way, the main objective of this work is to investigate the dynamic structural behaviour of a steel-concrete composite multi-storey building when subjected to human rhythmic activities （aerobics）. The studied structural model represents a typical interior floor bay of a commercial building used for gym and is composed by three floor levels spanning 20 m by 20 m, with a total area of 3×400 m2. An extensive parametric study was developed aiming to obtain the peak accelerations, RMS （root mean square） accelerations and VDV （vibration dose value） values, based on two different mathematical formulations. The human comfort of the building was analysed and the vibration transmissibility related to the steel columns was verified. Based on the found results, the investigated structural model presented high vibration levels that compromise the human comfort.

Application of the Principles of Lean Thinking in the Post Construction Department

The increase on the competitiveness, the search on the customer satisfaction, the search by reducing waste in the civil construction were facts which helped entrepreneurs and companies to seek new ways of working, being lean construction one of the ways to get that. Studies report that the application of the lean tools in construction was carried out in an isolated way. This type of application was pointed as a major factor limiting the extent of achievement in implementing lean principles. The aim of this studies is to identify opportunities to implement the principles of lean production in the service department of a construction company in Goi^is, proposing routines that try to implement the continuous improvement of its processes, eliminating waste, reducing the lead time, allow it to perform the mapping processes, applying the just-in-time and among others, providing services that add value to the customer satisfaction. It was possible to establish the average time for each step, allowing to identify possible improvements in the department, from the perspective of lean principles. The research paper concludes by pointing out the activities for the Department of Post Construction work from building companies, from lean concepts.

Evaluation of the Policies for Seismic Retrofit of Buildings

The Japanese government has established a law to Hanshin-Awaji Earthquake in 1995. This paper evaluates the incentives of the policies related to the law. The data shows achieved in 2018 if the current trends of improvement will supports the school retrofit works that are carried out by the promote seismic retrofitting of buildings immediately after the Great effectiveness, efficiency, administrative feasibility and technological that the policy target of seismic safety of existing buildings will be be continued. In the field of school buildings, national government local governments, using the guideline for school retrofit. However, there are still significant issues to make all buildings safe. One of the key challenges is how to persuade the elderly who would not invest their money to improve their old houses. Another challenge is to make owners understand the importance and have priority in improving the seismic safety of buildings. Currently many efforts are taken by the local governments, such as holding seminars for local communities, preparing financial support schemes, providing consultancy for seismic assessment and making earthquake hazard maps. This paper also provides comments on the improvement of the current policies for promoting seismic retrofit based on some international experiences in retrofit of buildings.

Effect of Curing Temperature on Mortar Based on Sustainable Concrete Material＇s and Poly-Carboxylate Superplasticizer

Nowadays, technologies in construction field have offered several kinds of chemical admixtures, which offer different behaviors at the fresh state of the batch and by consequence, it is resulted with different mechanical behaviors at the solid state of the mix. This study focused on the behavior of a new kind of admixture at fresh and solid states. Currently, the concrete material has become a very expensive material because the high price mostly of aggregates, representing the three quarters of the concrete components. By consequence, it costs money and on the other hand, it produces a lot of wastes. The main aspect which guides this study is to make a kind of concrete based mainly on local material and sustainable concrete material （SCM or waste material）, which is one very abundant material in quality and quantity, under the current tendency the results obtained in this study summarize up the importance of the temperature during the development of the mechanical characteristics of mortar, mainly on compressive strength at age of 28 days. This is in the case of the addition of limestone crushed additive by percentage of substitution.