Ultra High-rise Buildings Research Articles

Investigation of elevator-aided evacuation strategies for older people in high-rise elderly housing

Staircase evacuation is the major means of fire evacuation for current high-rise residential buildings. However, its feasibility may be questioned as the increasing aging population and many recent constructions of elderly community estates comprising high-rise apartment buildings. The weakness in physical strength and mobility impairment of older people may impede the successful implementation of staircase evacuation. Therefore, it is reasonable to consider facilitating older people's evacuation with elevators, shorted as elevator-aided evacuation (EAE). In order to find the most appropriate EAE strategy for high-rise elderly housing evacuation, three possbile strategy modes for EAE are proposed: horizontally rationed EAE (S1), vertically rationed EAE (S2), and refuge floor gathered EAE (S3). Using evacuation simulation to examine evacuation efficiencies of these proposed strategy modes varying in different evacuation scenarios, we find that S2 is appropriate for middle high-rise building (12 & 24 stories) evacuation; S3 is suitable for ultra high-rise building (36 & 48 stories) evacuation with a low occupants' density per floor; S1 is the most preferable for evacuation of ultra high-rise buildings (36 & 48 stories) with a high occupants' density per floor. More importantly, the ratio of occupants assigned to use elevators and stairs for evacuation needs to be regulated according to the occupancy information. Thus, a smart elevator-aided building fire evacuation scheme is suggested, which aims to determine the optimal EAE strategy according to the real-time on-site situation.

Experimental and analytical investigation on precast concrete-encased concrete-filled steel tube column-to-column dry connections under axial tension

Precast technologies featuring rapid construction and reduced on-site manpower have been gaining widespread adoption in the construction industry, particularly in reinforced concrete (RC) structures and composite steel–concrete structures over the past few decades, due to rising labour cost. However, to date, no workable precast connections have been developed for concrete-encased concrete-filled steel tube (CECFST) columns, which are increasingly used in ultra high-rise buildings and large-span bridges owing to its superior structural performance and excellent fire resistance. In this regard, to promote applications of CECFST columns in countries with increasing labour cost, this study develops two innovative precast CECFST column-to-column dry connections (PCDCs), through which the construction of CECFST structures would minimise heavy on-site work, such as welding or grouting of joints, formwork, and propping systems. Ten laboratory tests including four component tests and six column-to-column connection tests, were conducted to investigate tensile performance of the developed PCDCs. Key test results of all the ten specimens, such as load versus deformation relationships and failure modes, showed that the PCDCs had excellent tensile resistance and ductility. Furthermore, this paper carried out a series of theoretical analyses to quantify the ductility and tensile strength of the PCDCs through proposed load transfer mechanisms and component-based models. The design method of the PCDCs was presented by a simple flowchart and a worked example. With excellent structural performance, the PCDCs developed in this paper demonstrated huge potential to replace conventional cast-in-place (CIP) connections of CECFST columns.

Triaxial Concrete Constitutive Model for Simulation of Composite Plate Shear Wall–Concrete Encased: THUC3

A new triaxial constitutive model [Tsinghua University Concrete Three-dimensional (THUC3)] of concrete was developed for high-fidelity finite-element (FE) simulation of composite plate shear wall–concrete encased (C-PSW/CE), which has been adopted as the lateral force-resisting system in numerous ultrahigh-rise buildings. In this formulation, a uniaxial constitutive model of concrete was introduced. The following five key features of concrete were included in the proposed model: compressive softening of unconfined and confined concrete, tension softening, pinching effect, shear softening, and strength degradation due to principal tensile strain. A triaxial constitutive law was also illustrated based on a fixed crack assumption. By assuming that the stress of the concrete can be decoupled in the crack coordinate system upon initial cracking, the triaxial constitutive law was assembled from the aforementioned uniaxial stress–strain relations. A new formulation is proposed to achieve strain decomposition and stress assembly in three-dimensional stress space. The numerical implementation of the stress update algorithm in an ABAQUS user material (UMAT) subroutine was illustrated. The modeling scheme and material constitutive laws of reinforcing bars, steel plates, and studs were also introduced. Subsequently, the developed triaxial constitutive model was validated at the material level by simulating the cyclic behavior of concrete and reinforced concrete (RC) specimens. The developed FE model showed good accuracy in simulating the hysteretic behavior, ultimate capacity, and residual strain in cyclic tensile loading. Two flexural critical C-PSW/CE tests, Specimens C30-5 and C40-5, were also completed and reported in this research, and 18 shear critical C-PSW/CE tests were collected from the existing literature. These tests were simulated to further validate the developed model at the structural level. Comparisons indicated that the proposed model showed a reasonable level of accuracy in terms of ultimate capacity, energy consumption, and failure mode. In addition, the modeling of studs by a nonlinear connector element is recommended based on comparisons between the test and FE results. The current AISC provisions for shear capacity of C-PSW/CE specimens were also evaluated relative to the computational and experimental results.

Application of Mobile Mechanical Arm in Curtain Wall Installation of Xinhua Star

Chengdu Xinhua Star Project is designed by integrating insert unit elements with aluminum panel boxed eave. Because the unit elements are installed between the upper and lower floors, the traditional vertical lifting process cannot meet the installation requirements. Therefore, this project uses the mobile mechanical arm developed by our company for installing unit element indoors. The mobile mechanical arm is 3045×1699×1320mm with the rated load of 600kg, the self-weight of 1750kg and the counterweight of 600kg. It can be disassembled or separate transportation and has the functions of free displacement, three-dimensional adjustment and absorption and grabbing. During construction on site, first of all, the grid lines, finished surface line, and bottom and top locating lines of the adapting piece of the unit element are clearly marked and set out on the main structure. According to the geometric dimension of the mechanical arm and the locating line of the curtain wall, the movement locating line of the mechanical arm is drawn. Then, the mechanical arm is operated indoors for installation. The indoor installation process of curtain wall explored by this project provides a new idea for the construction of the unitized curtain wall of ultra-high rise buildings. It can alleviate the construction difficulty of the unitized curtain wall, reduce the safety risks and measure costs of outdoor installation of the unitized curtain wall of ultra-high rise buildings, thus being a new type of curtain wall construction process that is worthy of promotion and application.

Event-driven modeling of elevator assisted evacuation in ultra high-rise buildings

In the past few decades, numerous ultra high-rise buildings have been erected in the metropolitan areas of many cities around the world. For the related building designers, building occupants and the governments, fire safety problem is certainly a major concern, especially after the collapse of World Trade Center in the 9/11 event. That disaster makes people reconsider ultra high-rise building evacuation strategies. Of the current strategies, using elevators in ultra high-rise buildings to assist evacuation seems to be promising in improving evacuation efficiency. To quantitatively evaluate elevator assisted evacuation process, an event-driven agent-based modeling approach is proposed in the present paper. This modeling approach could capture not only the movement characteristics of stair-using occupants but also the detailed elevator motion features. The combined effects of occupants’ and elevators’ parameters on the evacuation efficiency have been investigated. Results indicated that the model is helpful to reveal the dynamics of elevator assisted evacuation, and sometime, using elevators to move all occupants to ground safety point may not be an optimal solution.

Construction Quality Control Measures of Conversion Layers in Ultra High-Rise Buildings

<p>Construction quality directly affect the structure safety of high-rise building. Especially the construction quality of the conversion layer in ultra high-rise buildings plays an important role for the overall quality of ultra high-rise buildings. This article mainly discusses and analyzes the key points, difficulties and quality control in construction of conversion layer, in order to better control the quality of conversion layers in ultra high-rise buildings and build better buildings.</p>

Construction Quality Control Measures of Conversion Layers in Ultra High-Rise Buildings

<p>Construction quality directly affect the structure safety of high-rise building. Especially the construction quality of the conversion layer in ultra high-rise buildings plays an important role for the overall quality of ultra high-rise buildings. This article mainly discusses and analyzes the key points, difficulties and quality control in construction of conversion layer, in order to better control the quality of conversion layers in ultra high-rise buildings and build better buildings.</p>

The Discussion on Construction Engineering Technology on Ultra High-rise Building

<p>With the speeding up of urbanization and increasing of urban population, the urban land resources are increasingly scarce. Emergence of ultra high-rise building is an inevitable trend. At present, our construction industry is in the rapid development period, where the proportion of ultra high-rise buildings in urban architecture of many big cities constantly increases. The improving ultra high-rise engineering technology is an important part of the construction industry in our country. This paper will analyze the ultra high-rise construction technology of building work in detail.</p>

The Discussion on Construction Engineering Technology on Ultra High-rise Building

<p>With the speeding up of urbanization and increasing of urban population, the urban land resources are increasingly scarce. Emergence of ultra high-rise building is an inevitable trend. At present, our construction industry is in the rapid development period, where the proportion of ultra high-rise buildings in urban architecture of many big cities constantly increases. The improving ultra high-rise engineering technology is an important part of the construction industry in our country. This paper will analyze the ultra high-rise construction technology of building work in detail.</p>

내구성 시험에 의한 초고층 건축물 선형조인트 충전시스템의 내화 성능 평가

초고층 건축물은 좁은 평면위에 수직적으로 집합된 구조물이다. 이러한 건축물에 화재 시 수직으로의 화재확산은 엄청난 인적 물적 자원의 피해를 초래하게 된다. 이러한 화재확산을 막기 위한 방화구획의 설정은 아주 중요하며 방화구획에 틈이 발생하는 경우 화재확산의 통로가 되게 된다. 선형조인트 충전시스템은 이러한 화재확산을 막는 중요한 요소가 된다. 지금껏 선형조인트 충전시스템은 내화성능에만 초점이 맞추어져 있었으며, 건축물의 움직임 대한 내구성을 전혀 고려하지 않았다. 본 연구는 초고층 건축물의 움직임을 고려한 내구성 시험방법과 기준을 ISO 국제표준에서 도입하여 이를 적용한 시험 장치를 개발하였고, 내구성 시험과 내화시험을 실시하였다. 시험체는 암면을 선형의 틈에 채우고 상부에 fire-stop spray를 적용하는 가장 일반적인 형태의 선형조인트 충전시스템(시험체 1)과 시험체 1에 단열재를 포함한 시험체(시험체 2)의 시험을 실시한 결과 시험체 1은 180분의 내화성능을 발휘하였으나, 시험체 2는 153분의 내화성능을 나타내었다. 시험체 2는 차열성능에는 문제가 없었으나 단열재 부분에 불꽃이 발생하여 차염 성능을 상실한 것으로 밀도가 낮은 단열재를 통해 화재확산이 이루어져 추후 연구에서 단열재를 포함한 외벽 커튼월 시스템의 선형조인트 충전시스템에 대한 내화성능의 연구가 필요할 것으로 사료된다. It is well known that ultra high-rise buildings are constructed to accommodate many facilities in a limited area. However, in this type of buildings, the spread of fire to the upper floor can cause immense financial loss and casualties, compared to normal sized buildings. Hence, to prevent the loss due to the spread of fire, it is recommended that each room or space of building structures should be separated by fire-proof barriers or fire-proof walls. The linear joint system is a key area to determine the spread of fire, so that the gap in the joint must be fully protected from fire. In Korea, it is true that the linear joint applied to practice does not take account the effect of natural thermal movement of building structures that can deteriorate the fire-proof performance of the system. Thus, in this study, a ISO movement test was adopted to reflect the long term condition of the linear joint system in a real world. A new apparatus was developed and used in the tests, in order to follow the ISO code. In this study, two specimens were prepared for a comparison purpose: one is conventional specimens (specimen 1) and the other is the specimen with additional insulation (specimen 2). Mineral wool and fire-stopping spray were the conventional materials, applied to specimen 1, and glass wool was an additional material applied to specimen 2, together with the mineral wool and fire-stopping spray. Test results showed that specimen 1 resisted fire-induced damage for 180 min, whereas specimen 2 did for 153 min. As expected, the fire-proof performance of specimen 2 was better than specimen 1. However, the results obtained from the specimen 2 still did not satisfy the required level. This was due to the ignition of glass wool. Hence, it is required to further explore to find the other insulating materials that can increase the fire resistance time.

Experimental study on an ultra high-rise building evacuation in China

With the development of modern cities, more and more ultra high-rise buildings have been built. Emergency evacuation of such buildings becomes one of the major concerns for building designers, building occupants and governments, especially after the disaster of 9/11. In this study we designed three experiments to investigate the process of ultra high-rise building evacuation. The experiments were performed in Shanghai World Financial Center, which is about 470m tall. In the first experiment, the evacuation of a single pedestrian from the top floor to the first floor was performed. Movement characteristics such as mean speed and the time needed for evacuation were analyzed. In the second experiment, the mass evacuation process was captured by video cameras and the data were extracted out manually. The evacuees were distributed initially on floors 12–17, and were asked to evacuate through a staircase onto the refuge floor. On the refuge floor, i.e. the 6th floor, the evacuees were required to transit into another staircase to keep moving down to the ground floor. The characteristic space–time curves for each evacuee were extracted and analyzed. Parameters such as the mean speed and the evacuation time, as well as the characteristic of the transit process from one staircase to another were investigated. We at last mimicked and discussed the process of lift evacuation for an ultra high-rise building in the 3rd experiment. Evacuees located on the 41st and 65th floor were asked to move downward by stairs until they came to the refuge floors, where they would evacuate to the ground floor by lifts. The time characteristic of the mixed evacuation strategy was discussed. The basic data obtained from the experiments are useful for building designers and can be used to validate and refine ultra high-rise building evacuation models.

An Artificial Neural-network Based Predictive Model for Pre-evacuation Human Response in Domestic Building Fire

The post-1993 WTC attack study (Proulx and Fahy, In: Proceedings of ASIAFLAM’95—An International Conference on Fire Science and Engineering, Hong Kong, 1995, pp 199–210) revealed that occupants took 1–3 h to leave the 110-storey buildings, and the pre-movement reactions could account for over two-thirds of the overall evacuation time. This indicates that a thorough understanding of the pre-evacuation behavioral response of people under fire situations is of prime importance to fire safety design in buildings, especially for complex and ultra high-rise buildings. In view of the stochastic (the positions of the occupants) and fuzzy (uncertainty) nature of human behavior (Fraser-Mitchell, Fire Mater 23:349–355, 1999), conventional linear and polynomial predictive methods may not satisfactorily predict the people’s response. An alternative approach, Adaptive Network based Fuzzy Inference System (ANFIS), is proposed to predict the pre-evacuation behavior of peoples, which is an artificial neural network (ANN) based predictive model and integrates fuzzy logic (if-then rules) and neural network (based on back propagation learning procedures The ANFIS learning architecture can be trained by structured human behavioral data, and different fuzzy human decision rules. The applicability in simulating human behavior in fire is worth exploring.

Control Systems for Ultra-High Rise Elevators1

We present a scalable and tunable control design for controlling elevator vertical motion for ultra high-rise buildings. Scalability is desirable to enable customization to any hoistway while tunability enables periodic adjustments to normal wear and tear. We accomplish these objectives by first validating a scalable lumped parameter model that is based on a few prominent features in the vertical dynamics. A tunable controller based only on these features is developed and through simulations we show that the controller meets a set of standardized elevator performance tests while maintaining global exponential stability.