Roof Floor Research Articles

Correction: Experimental research on the structural instability mechanism and the effect of multi-echelon support of deep roadways in a kilometre-deep well.

[This corrects the article DOI: 10.1371/journal.pone.0192470.].

Study on Micro-expansive Concrete-Filled Steel Tube Support for Controlling the Stability of Surrounding Rock in Deep Roadway

The overall supporting capacity of ordinary concrete-filled steel tube support (CFSTS) can be decreased due to the self-shrinkage of concrete and the cracks of hardened concrete. The micro-expansive CFSTS is put forward in this paper. Firstly, the optimum proportion of micro-expansion concrete was determined by concrete strength testing. Then, the deformation of micro-expansion CFSTS and ordinary CFSTS under the same load w studied by numerical simulation. Finally, the micro-expansion CFSTS and ordinary CFSTS were applied to the roadway respectively. The results show: The expansive agent content and water reducer content is 11 and 0.5% in the optimum proportion of micro-expansive concrete, respectively. Under the same load, the deformation of the ordinary CFSTS was much larger than that of the micro-expansion CFSTS. The deformations of roof–floor and two sides of roadway supported by the micro-expansion CFSTS were obviously smaller than that of roadway supported by the ordinary CFSTS. The micro-expansion CFSTS has stronger supporting capacity than ordinary CFSTS.

Numerical Study of Smoke Spread upon Shaft-box Type Double Skin Facades

Abstract This paper presents numerical studies of smoke movement in the double skin facades type of Shaft-box. The room size is constructed with the reference of ISO9705 while the cavity width is selected to be 1m as the maximum fire hazard width. It turns out that when the smoke in the shaft is steady, the temperature in the shaft will change exponentially along with the height. Once the smoke enters the cavity, the toxicity hazard of smoke on the roof floor is the largest, under the action of Stack Effect and buoyancy created by the fire. And the room on the roof floor near the shaft towards the fire room is the most dangerous. The CO concentration of Room 3 on the roof floor reaches 200ppm within 4.5 min after the internal panes break.

Electrical System Design and Installation of New Building, Aisyiyah University, Yogyakarta

Aisyiyah University New Yogyakarta Building is one of the commercial buildings that moves the field of education in Yogyakarta. The New Building of Aisyiyah University Yogyakarta consists of 10 floors, including the basement floor, main floor and roof floor. Electric loads installed at the New Building of Aisyiyah University Yogyakarta include lighting loads (lights) and power loads (sockets) and the power loads of electric motors (air conditioners, elevators and others), which of course requires a large enough electricity supply. Electricity installed in the New Building of Aisyiyah University in Yogyakarta is 1010.9 kVA. The power supplied is 800 kVA from State Electricity Company and the total power capacity of the transformer is 1000 kVA and a generator set with a capacity of 1000 kVA. Where the backup power supply system is fully supplied by the generator set.

Effect of substrate depth, vegetation type, and season on green roof thermal properties

It is generally accepted that green roofs can influence thermal properties of a building, but there is some disagreement on the role that substrate depth and plant species plays in this equation. A study was conducted over a second floor roof in East Lansing, MI, comparing prevegetated mats of a mixture of sedum (depth=5cm) to a deeper roof (depth=20cm) planted with a mixture of 17 herbaceous perennials and grasses. Both roof sections were instrumented with heat flux sensors, thermocouples, moisture sensors, and infrared sensors, and ambient weather conditions were also continuously recorded by a weather station located on the roof. Data were collected for the period of almost a year to cover all four seasons. Also, the roofs were well established and had reached near 100% plant coverage by the time data collection commenced two years after planting. Most of the differences in temperatures and heat flux through the roof occurred during the summer or winter. During summer, the shallow sedum roof experienced more extreme fluctuations in diurnal substrate temperatures which tended to be warmer during the day, but cooler at night. Heat penetrating into the building on the sedum portion of the roof was consistently greater than the herbaceous section during the afternoon. However, during the night and early morning, heat gain into the building was greater on the herbaceous roof, especially on cloudy and rainy days. During winter, heat transfer through the sedum portion of the roof was affected more by outside environmental conditions, whereas the herbaceous portion of the roof was stable. Although, the sedum roof exhibited more extremes, when daily heat flux values were totaled for each month and each season, the herbaceous roof actually experienced more heat entering the building during the summer, but less heat escaping the building during the winter. This is an advantage during the winter months as the herbaceous roof would reduce heating costs. However, contrary to conventional logic that plants with high transpiration rates are superior, during the summer months the sedum roof outperformed the herbaceous roof.

Economic performance assessment of residential building retrofits: a case study of Istanbul

This paper presents an approach proposed for assessing economic performance of retrofit applications performed at functional building element level in residential buildings and exemplifies it for the city of Istanbul, which has a temperate-humid climate. This approach covers three steps. In the first step, typical buildings and their properties are determined by analysing the residential buildings in Istanbul, and then the retrofit alternatives are generated. In the second step, an economic impact analysis is performed for typical buildings by considering the costs during their life cycle phases. In the third step, a life cycle cost assessment is done according to the variables, which are defined as window-to-wall ratio (WWR), window system, thermal insulation material, orientation and building age. The most beneficial retrofits are lastly determined depending on their economic performance ratios (EPRs). In conclusion, insulating exterior wall, projected floors, floors above unheated space and roof floors separately provide the highest benefits at the age of 30, and the lowest benefits occur at the age of 15 for all WWRs. The highest EPRs are obtained for the WWR of 10% at all ages. The renewal with PVC frame provides benefit while the renewal with wooden frame causes losses. Orientation slightly affects the EPRs. The use of stone wool in the retrofit causes a reduction in the EPRs due to high investment cost of stone wool. When the 20-year-old building which has the WWR of 10% is insulated with extruded polystyrene and renewed with PVC, it provides the highest benefit of about 45%.

Thermophysical aspects of reconstruction of cold roof spaces

The results of theoretical studies of thermal modernization of cold roof floor. The designs of overlap of long-life roofs of public buildings were considered. Overlap of these buildings are made by wooden or concrete beams and made of concrete slabs with upward edges. The problems of thermal modernization of these designs are consideration of the impact of heat-conducting inclusions on the resistance to heat. The heat-conducting inclusions of constructions are beams and vertical edges of the slabs. The results of calculations of the temperature fields were used for the analysis. The research was carried for the two temperature zones which Ukraine’s territory is divided into. The analysis of thermal protection level of structures overlap was made. The magnitude of the impact of heat-conducting inclusions on resistance to heat after thermal modernization of cold roof floor was observed. The analysis showed that the thermal protection properties of structures less than standard, therefore the insulation of areas with heat-conducting inclusions is required. The options of insulation of these areas were considered. The optimal insulation options with the least amount of additional insulation over the heat conductive areas were selected.

Improving the Seismic Behavior of Symmetrical Steel Structures Under Near-Field Earthquake Using a Base Isolation Method Lead Rubber Bearing Isolator

<p>In this study, the function and application of seismic isolation system through lead rubber bearing isolator (LRB) in near-fault earthquakes are compared with fixed-base structures. As a result of their high frequency content, near-fault earthquakes impose huge energy on structures and cause severe damages. One of the appropriate solutions for this issue is the use of LRB which decreases the amount of imposed energy on structures. To improve the function of isolated structures under the near-fault earthquakes, isolators are designed in a way to tolerate the vertical component of earthquakes. To this purpose, we limit the displacements due to the horizontal movements of isolator through Gap spring which acts as a retaining wall and prevent shocks to other buildings. Moreover, this approach decreases the vertical movements of isolators and indirectly improves their behavior. In the current study, three buildings with four, eight, and 12 floors (with and without gap spring) were included. Isolators were manually designed in accordance with AASHTO-LRB regulations and the behaviors of both isolators and buildings are considered non-linear. Then we analyzed and compared the amount of energy, displacement, and acceleration of structure at the center of roof. The results indicated a significant decrease in the results of base shear, the acceleration of roof center, floors drift and energy imposed on the structure in the isolated system in comparison with the fixed-base structure.</p>

Research Precast Fool Slab of Massonry Building Roof Reinforcement Methods

Most of the existing building floor roof of brick structure is precast floor slab structures, which structural integrity is not good. In the earthquake, the floor is easy to fall off from the wall, causing casualties and economic losses. Vertical bearing capacity of precast floor slab are usually able to meet the requirements. In most cases the floors have been fall off from the wall before the floors were damaged, Stability of the outer plane of the floor itself to be adequate.By analyzing the patterns and characteristics of precast floor slabs crack under seismic force often appear, this paper presents that the prefabricated floor flat overall reinforcement scheme, which the application of steel band with end portion of the floor a holistic reinforcement,and finite element software ABAQUS be counted cases,the integrity of the reinforced floor to achieve significant improvement, and maximum allowable displacement can be controlled within a limited value.

The Research of Box Beam Warping Displacement Function

Based on the principle of minimum potential energy, choosing warping displacement function of parabolic displacement mode, using energy variational method to deduce Box beam shear lag effect analysis of differential equation to obtain shear lag warping stress. Through the calculation of simply supported box girder model and the analyse of the stress of Wide cantilever plate, box girder roof and box girder floor Assume a new warping displacement function. Through the analysis of measured results proved the rationality of this article assumes and research value.

Fracture evolution around pre-existing cylindrical cavities in brittle rocks under uniaxial compression

The development of fracture around pre-existing cylindrical cavities in brittle rocks was examined using physical models and acoustic emission technique. The experimental results indicate that when granite blocks containing one pre-existing cylindrical cavity are loaded in uniaxial compression condition, the profiles of cracks around the cavity can be characterized by tensile cracking (splitting parallel to the axial compression direction) at the roof–floor, compressive crack at two side walls, and remote or secondary cracks at the perimeter of the cavity. Moreover, fracture around cavity is size-dependent. In granite blocks containing pre-existing half-length cylindrical cavities, compressive stress concentration is found to initiate at the two sidewalls and induce shear crack propagation and coalescence. In granite blocks containing multiple parallel cylindrical cavities, the adjacent cylindrical cavities can influence each other and the eventual failure mode is determined by the interaction of tensile, compressive and shear stresses. Experimental results show that both tensile and compressive stresses play an important role in fracture evolution process around cavities in brittle rocks.

The Study on Roadway Layout in Coordination of Mining Coal Seams Base on Failure of Floor Strata

In order to make sure the reasonable roadway layout in lower seam of close coal mining group coordination in Lijiahao coal mine, firstly, applying the theoretical analysis and geological radar detection to get the influence depth of mining from the up coal seam 2-2 to the floor is about 20m, the results show that the thickness of complete strata is about 15m, then determining to use the outward alternate entries in lower seam roadway by using theoretical analysis. At last, determining the distance of outward alternate entries is 12-14m by using FLAC3D numerical simulation software to simulate the change of stress and displacement in roof floor and two sides of roadway.

Research of Artificial Sites Green Roof for Energy-Saving Efficiency in Taiwan Taichung

In this study, set the empirical plane pilot area planting the groove (long 425cm × width 300cm × Height 20cm ) in the Taichung City residential area on the second floor roof, planting the groove bottom-up sequence laying frame high-rise, water proof layer, drainage layer,filter layer (non-woven, water-pottery-stone), the medium layer and planting of layer, planting the groove around the hollow brick interval income side to lighten the load. Noon hours exposed roof temperature of 25.49-37.56°C, green roofs surface only at 16.45-24.69°C, 17.74-24.79°C indoor temperature on the second floor, effectively prevent the roof surface temperature rise, and thus reduce the interior roof of the second temperature7.75-12.77°C. Building green roofs to cooling, mainly to reduce the building temperature, reducing air conditioning electricity consumption , accomplish cooling and energy-saving benefits.Compare different annual electricity consumption in the same period, extensive green roof to total electricity consumption of 860 K.Watts/hours , exposed roof to total electricity consumption in 1767 K.Watts/hours, 48.67% of the electricity consumption savings, to achieve energy efficiency.

Poem in the order and tradition: Bibliothek 21

Poem in the order and tradition: Bibliothek 21

Studying the Vulnerability of Steel Moment Resistant Frames Subjected to Progressive Collapse.

The guidelines of Unified Facilities Criteria (UFC) and U. S. General Service Administration (GSA) provide the design requirements to reduce the potential of progressive collapse for structures. According to these codes, progressive collapses are occurred due to loss of a main vertical structural element. In this study, the vulnerability of an official 10-story steel moment resistant frame, designed according to Iranian National Building Codes (INBC) is assessed. The following nonlinear dynamic analysis procedure is recommended by the UFC 4-023-03 guideline, which provides technical guidance for mitigation and protection of progressive collapse. Alternate Path (AP) method has been applied to evaluate the structure that can bridge over notionally removed column and nonlinear dynamic analysis procedure conducted. The investigated cases emphasize on the removal of a corner column in the ground floor, fifth floor, eighth floor, and just below the roof floor. Based on the results obtained in this research, steel moment resistant frames, designed according to Iranian National Building Codes, do not satisfy UFC acceptance criteria and have high potential for progressive collapse in corner column removal scenarios. Therefore some modifications have been conducted on the codes to satisfy the UFC limits.

Vibra-Acoustic Characteristic Matching of Mini-Car Body Structure and Interior Acoustic Cavity in Low Frequency Range

This paper focused on the interior boom noise of a mini-car when driving at high speeds. Vehicle interior noise rotor drum tests in semi-anechoic room showed that vehicle interior boom noise in narrow frequency band exited near 250Hz. Structural and acoustic finite element analysis certified the front roof and rear floor coupled with interior acoustic cavity around this frequency, causing acoustic cavity resonance. On the base of sensitivity analysis technology, a structural improvement schemes pasting free damping fin on the front roof and rear floor of mini-car body for vibration and noise reduction was proposed. Finite element Modal analysis of the mini-car body after improving indicated that local modal amplitude of the mini-car body at the front roof and rear floor around 250Hz was controlled effectively. Mini-car rotating drum test results after improving showed that vehicle interior boom noise was decreased obviously after pasting free damping fin at the front roof and rear floor. The improving schemes and noise reduction effects proposed in this paper were validated.

Study on Zoning of Overburden Strata and Roadway Deformation of Ascending Mining in Thin Coal Seam

In order to solve the problems appeared in mining process of upper seam in Xiaohezui coal mine, a technical scheme of ascending mining was put forward. UDEC, a discrete element numerical simulation soft was used to study the characteristics of zoning of overburden strata and the rule of vertical stress distribution of the upper coal, the results show that the upper coal is on the top of the equilibrium belt without step dislocation, the structure of roof stratum and floor stratum stay complete with slight separations, so ascending mining is feasible; the range of the upper coal influenced by the stoping of below working face is -85m~65m, the vertical stress reaches a maximum 15m ahead the below working face, and reaches a minimum behind it 25m. It is applied in the engineering practice, the roadway deformation discipline of the upper coal is similar to the distribution rule of vertical stress, provides a theoretical basis for guiding and improving the roadway support of ascending mining.

How to Build Affordable but High Quality Houses for Villagers: Appropriate Design for Aini Vernacular Houses in Xishuangbanna

Yunnan is very rich in natural resources, and using natural materials for building is an ancient tradition in local minority. In the remote poverty national areas, we always concern about making use of appropriate technical means, following the tradition of local construction, and efficiently applying local natural building materials. In addition, we pay close attention to improving their living quality effectively by the techniques. In this article, from a specific practice casethe United Nations GEF small grants programme, we make multiple detailed comparative analysis with traditional houses at the first, next we discuss appropriate design in the new residential construction of Aini in Xishuangbanna. And then we focus on using the local natural building materials such as bamboo, wood, adobe and other materials, by which we can make the improved design on roof system, wall system and floor system, so as to reduce construction costs and technical complexity, as well as we can effectively improve the living quality of construction at the same time. A demo project was constructed to show how these natural materials were integrated into a system to form the whole building. Joint team consists of local craftsmen and engineers constructed the demo-project so that the technology can be localized.

Performance Evaluation of TMD under Typhoon Using System Identification and Inverse Wind Load Estimation

Abstract: The typhoon behavior and performance of a tuned mass damper (TMD) are presented based on the system identification and the inverse modal wind load estimation. The TMD was installed on a 39‐story, 184.6‐m steel building located in Incheon, Korea with a monitoring system consisting of an anemometer, accelerometers, and internet‐based data logging system. On September 2, 2010, the building experienced the Kompasu Typhoon, in which the peak wind speed, measured by an anemometer installed on the roof floor, was 49.7 m/s. To analyze the behavior of the building during the typhoon, the dynamic properties of building and TMD are identified from the measured responses. The modal wind load is then inversely estimated from the TMD and building accelerations using a Kalman filter, and the vibration reduction performance of the TMD is evaluated. The analysis results show that the typhoon‐induced vibration was reduced significantly due to the installation of TMD.

인접건축물의 진동제어를 위한 MR감쇠기의 위치 선정에 관한 연구

최근 인접 건축물의 진동제어와 관련된 연구가 몇몇 연구자에 의하여 수행되고 있으며 그리고 구조물의 지진동 제어를 위하여 준능동 감쇠기의 일종인 MR 감쇠기가 적용되고 있다. 본 논문에서는 MR 감쇠기의 위치에 따른 인접 건축물의 지진동 제어성능을 분석하여 MR 감쇠기의 설치에 대한 최적의 위치를 선정하고자 한다. 본 연구를 위하여 인접한 20층과 15층 건축물을 예제 구조물로 사용하였으며 이 예제 구조물은 서로 다른 고유진동수를 갖게 하였으며 예제 구조물의 지진동 제어를 위하여 Groundhook 제어기법을 적용하였다. 예제 구조물의 수치해석에 의한 지진응답 분석결과, 변위응답 제어를 위하여 인접 건축물의 최상층에 MR 감쇠기를 설치하는 것이 제어성능에 있어서 우수하며 가속도응답을 제어하기 위해서는 인접 건축물의 중간층에 MR 감쇠기를 설치하는 것이 우수한 제어성능을 보이고 있다. MR 감쇠기를 중간층에 설치할 경우에, 변위응답과 가속도응답을 동시에 제어가 가능하다. 따라서 건축물의 제어 목표에 따라서 MR 감쇠기 설치위치를 적절하게 선정해야 할 것이다. In recently, the vibration control of adjacent buildings have been studied and magneto-rheological(MR) fluid dampers have been applied to seismic response control. MR dampers can be controlled with small power supplies and the dynamic range of this damping force is quite large. This MR damper is one of semi-active dampers as a new class of smart dampers. In this study, vibration control effect according to the installation location of the MR damper connected adjacent buildings has been investigated. Adjacent building structures with different natural frequencies were used as example structures. Groundhook control model is applied to determinate control force of MR damper. In this numerical analysis, it has been shown that displacement responses can be effectively controlled as adjacent buildings are connected at roof floors by MR damper. And acceleration responses can be effectively reduced when two buildings are connected at the mid-stories of adjacent buildings by MR damper. Therefore, the installation floor of the MR damper should be selected with seismic response control target.