Vault Roof Research Articles

Excavations at Late Bronze Age tombs of Lori Berd

During the 2007-2008 field season seven tombs were excavated at Lori Berd. Four of these date to the end of the Late Bronze Age. One of the largest tombs (Tomb 81) of the site is located nearly in the centre of the cemetery, 70 m south of the Stepanavan-Lori Berd road. The oval (13.5 × 6.1 m) burial mound was composed of stones and soil, measured 0.6 m high. The centre was slightly sunken: it had a flat surface, and was oriented to the northwest – southeast. Sixteen large slabs forming the false vaulted roof of the burial chamber were discovered 0.2 – 0.4 m below the grass-covered mound. The four central stones were placed in the horizontal position, while the parameter stones were leaning towards the chamber.

Large eddy simulation of unsteady aerodynamic behavior of long-span vaulted roofs

This paper discusses the unsteady aerodynamic behavior of long-span vaulted roofs. First, a forced vibration test in a turbulent boundary layer is conducted in a wind tunnel. The models are force vibrated in the first anti-symmetric mode to investigate the effects of wind speed, rise/span ratio, and the amplitude and frequency of forced vibration on the distributions of wind pressures and unsteady aerodynamic forces. Then, a large eddy simulation (LES) is carried out to clarify the physical mechanism of wind-roof interaction as well as to investigate the influences of a roof’s vibration on the flow field around the roof. From the results of the wind tunnel experiment and the LES, we discuss the characteristics of unsteady aerodynamic forces on a long-span vaulted roof over a wide range of the reduced frequency of vibration. The effect of unsteady aerodynamic forces on the dynamic response of the roof is also discussed. A comparison between the wind tunnel experiment and the LES indicates that the LES can be used effectively to evaluate the unsteady aerodynamic behavior.

State-of-the-art in development of diffuser augmented wind turbines (DAWT) for sustainable buildings

In this paper, a review of the development of Diffuser Augmented Wind Turbines (DAWT’s) into the Built Environment has been presented. DAWT’s offer a lot of potential as electricity providers in areas where it is needed, such as in the built environment. Research into DAWT’s has revealed that flow along a building significantly affects inlet conditions to the rotor due to flow separation at the leading edge. Adjusting the area ratio, length/diameter ratio as well as diffuser design can improve the performance of the free-standing DAWT significantly. Placing the turbine at the centre of a roof is found to allow the best wind conditions to the wind turbine. It was found that a turbine can be placed at a height 1.3 times the height of a small building for the best results. It has been found that vaulted roof’s encourage acceleration of air flow better than other topologies. Furthermore, a recent approach to building-integrated wind turbines involves a flow-enhancing architectural design for buildings to improve favourable inlet conditions to a DAWT.

Revalorization of Structural Floor Systems in the Twentieth Century: An Overview

Abstract Towards the end of the nineteenth century and the beginning of the twentieth century new technological evolutions and material developments gave rise to different modular structural flooring systems, which allowed light but strong floors to be constructed. This paper gives an overview of the evolution in flooring systems, their durability problems, and how to solve them. Similar systems also have been used for roof constructions. The strengthening of an atypical vaulted roof structure in the “Het Depot” theatre in Leuven, composed of terracotta arch and panel elements, showing its specific problematic and its specific revalorization approach serves as a case study to illustrate the methodologies applied.

Safety Problem Of Cavity Under Open Pit Bench

Abstract Some open pits in China are severely threatened by hidden cavities under benches which are always inaccessible and unmapped. The first thing to be well considered is safe and precise cavity detection, as the conventional detection methods cannot output a clear cavity vision, a three-dimensional laser measurement system is employed to perform detection, which is deployed from the surface through boreholes. The results from the scanner demonstrated very well the detailed level of information that can be collected in a cavity using this method, with the cavities’ layout under various benches being fully mapped. As detected cavities are always in horizontal and vaulted roof shape, two different theoretical calculation methods are proposed to analyze the cap rock stability for different roof shape. And also, the three-dimensional solid model generated through scanned laser data is used for stability numerical simulation by converting the data format into the one that recognized in corresponding software. Furthermore, acoustic emission technique is adopted to carry out long term real time rupture monitoring in cap rock, and four kinds of typical monitoring results are discussed which represent the rupture behavior in cap rock of unstable cavity, stable cavity, cavity with large working drill above and cavity beside explosion site. Thus, a complete safety evaluation system for such cavity will be established to ensure safe operation above.

Reducing cooling demands in a hot dry climate: A simulation study for non-insulated passive cool roof thermal performance in residential buildings

In hot dry climates, it is estimated that almost half the urban peak load of energy consumption is used to satisfy air-conditioning cooling demands in summer time. Since the urbanization rate in developing countries – like the case in Egypt – is rising rapidly, the pressure placed on energy resources to satisfy inhabitants’ indoor comfort requirements is consequently increasing too. This paper introduces passive cool roof as a means of reducing energy cooling loads for satisfying human comfort requirements in a hot climate. A designed algorithmic hybrid matrix was used to simulate 37 roof design probabilities alternating roof shape, roof material and construction. The result of using a vault roof with high albedo coating shows a fall of 53% in discomfort hours and saves 826kWh during the summer season compared to the base case of the conventional non insulated flat roof in a typical Cairo residential buildings. It is recommended that the selected cool roof solution be combined with natural ventilation to increase the indoor thermal comfort, and with passive heating strategies to compensate the increase in heating hours. The application is intended for low cost residential buildings in a hot dry climate.

A study of vaulted roof assisted evaporative cooling channel for natural cooling of 1-floor buildings

The application of evaporative cooling technique in a 1-floor stand-alone house with vaulted roof, in order to meet the required thermal needs of inhabitants and natural cooling of the interior space, has been studied in this paper. In order to investigate the capability of the system to meet thermal comfort conditions in different environmental conditions, the performance of the system has been numerically investigated for wide ranges of wind velocities, ambient air temperatures and relative humidity values. The results indicate that when the wind velocity is higher than 0.4m/s, the air inside the building will be ventilated efficiently. In addition, as the wind velocity or the ambient air temperature increases, thermal comfort is achieved at lower values of relative humidity. The maximum allowable values for relative humidity of the ambient air to meet thermal comfort conditions are calculated based on the adaptive thermal comfort standards, and the application of the proposed system in stand-alone buildings for the centers of the provinces of Iran is investigated.

Numerical Modelling of Historic Vaulted Timber Structures

Historic timber structures forming vaulted roofs of public and ecclesiastical buildings are present worldwide. The structural response of these constructions is usually governed by the structural performance of the joints, the interaction between the timber structure and the masonry parts, and the current condition of both joints and timber members. At present, numerical approaches, such as finite element method-based approaches are well-established tools for investigating the global response of complex historic structures. Using a FE-based software package, the authors developed a numerical model of a portion of an existing historic vaulted timber structure, which is part of the roof of the Cathedral of Ica in Peru, considering the in-plane semi-rigid response of the planked arches in the elastic range. For this purpose, the rotational and shear stiffness of the joints and the properties of the materials, which are assumed in good conditions, are calibrated by comparing the numerical outputs with experimental results available in literature. The aim of the work presented here is to compare the response of the same vault assuming either continuous (planks continuously connected) or discontinuous arches (modelling of the semi-rigid response of the joints which connect the planks together).

Non-linear stability analysis of a hybrid barrel vault roof

This paper focuses on the buckling capacity of a hybrid grid shell. The eigenvalue buckling, geometrical non-linear elastic buckling and elasto-plastic buckling analyses of the hybrid structure were carried out. Then the influences of the shape and scale of imperfections on the elasto-plastic buckling loads were discussed. Also, the effects of different structural parameters, such as the rise-to-span ratio, beam section, area and pre-stress of cables and boundary conditions, on the failure load were investigated. Based on the comparison between elastic and elasto-plastic buckling loads, the effect of material non-linearity on the stability of the hybrid barrel vault is found significant. Furthermore, the stability of a hybrid barrel vault is sensitive to the anti-symmetrical distribution of loads. It is also shown that the structures are highly imperfection sensitive which can greatly reduce their failure loads. The results also show that the support conditions pose significant effect on the elasto-plastic buckling load of a perfect hybrid structure.

Non-linear stability analysis of a hybrid barrel vault roof

Non-linear stability analysis of a hybrid barrel vault roof

Numerical Simulation of the Failure Propagation of Masonry Buildings during an Earthquake

The process of failure propagation of masonry buildings during earthquakes is simulated using a refined version of the distinct element method that simulates three-dimensional elastic, failure, and collapse behaviors of structures. Models with a flat roof and models with a vault roof are considered, and their failure propagation mechanisms are examined. The influence of the direction of the input ground motion on failure propagation is also investigated. Moreover, the effectiveness of three reinforcement measures is compared. One measure is increasing the mortar strength, the second is increasing the thickness of the bearing walls, and the third is introducing wooden columns and beams. Among these measures, increasing the mortar strength is found to be the most effective. Increasing the thickness of the bearing walls and introducing wooden columns and beams are found to be effective only if the roof has sufficient integrity since the collapse of the roof depends on the integrity of the bearing walls and the roof itself.

GENETİK, ÇEVRESEL VE KÜLTÜREL ETMENLERİN IŞIĞINDA ANEMİ: BAZI ESKİ ANADOLU TOPLULUKLARINDAN ÖRNEKLER

GENETİK, ÇEVRESEL VE KÜLTÜREL ETMENLERİN IŞIĞINDA ANEMİ: BAZI ESKİ ANADOLU TOPLULUKLARINDAN ÖRNEKLER

Frontobasal Fractures: Anatomical Classification and Clinical Significance

Frontobasal injury is a classic craniomaxillofacial fracture affecting the anterior cranial base. No data exist regarding the degree of frontobasal injury and associated midfacial fractures. The authors propose a classification of frontobasal and midface fractures involving the cranial base based on cadaveric experiments and comprehensive clinical experience. An institutional review board-approved retrospective review was conducted on patients with frontobasal fractures from 1995 to 2005. Fractures were categorized by pattern, location, midfacial involvement (impure), and complications compiled. One hundred five cadaveric heads underwent blunt impact to the frontal bone and upper midface. Calvarial vault, cranial base, and midface fracture patterns were categorized. Three frontobasal fracture patterns were identified. Isolated linear cranial base fractures constitute type I. Vertical-linear fractures of the skull vault (frontal bone) occur in combination with base fractures, representing type II (vault and base). Comminution of the frontolateral skull vault and orbital roof in association with a linear base fracture constitute type III. Two hundred ninety patients were identified with 49 complications (cerebrospinal fistula, 24; and infectious 25). Type III (n = 159) had the highest complication rate (impure, 29 percent; pure, 17 percent), followed by type II (impure, 19 percent; pure, 5 percent). There is essentially no extension of midface fractures to the cranial vault. Frontobasal fractures have three unique and reproducible patterns based on vector, location, and force. This new classification scheme, paired with known patterns of midfacial injuries, assists in fully understanding frontofaciobasal injury and its complications. Overwhelmingly, impure type II and any type III fractures are associated with a high rate of complications and must be carefully managed.

A model for estimation of daylight factor for skylight: An experimental validation using pyramid shape skylight over vault roof mud-house in New Delhi (India)

A model to estimate daylight factor was investigated and validated using experimental hourly inside and outside illuminance data of an existing skylight integrated vault roof mud-house in composite climate of New Delhi. The daylight factor model was found in good agreement with experimental value of daylight factor. This model was modified for different practical horizontal surface levels inside the big and small dome rooms and validated using experimental measured data. The yearly average value of percentage daylight factor for big and small dome skylight rooms was determined as 2% and 6%, respectively. The total annual average artificial lighting energy saving potential of the skylight illuminance in the existing building was estimated as 973 kW h/year; corresponds to 1526 kg/year of CO 2 emission mitigation. Hence, the annual carbon credit potential from skylight mud-house building is € 15.3/year.

The causes of porotic hyperostosis and cribra orbitalia: A reappraisal of the iron‐deficiency‐anemia hypothesis

Porosities in the outer table of the cranial vault (porotic hyperostosis) and orbital roof (cribra orbitalia) are among the most frequent pathological lesions seen in ancient human skeletal collections. Since the 1950s, chronic iron-deficiency anemia has been widely accepted as the probable cause of both conditions. Based on this proposed etiology, bioarchaeologists use the prevalence of these conditions to infer living conditions conducive to dietary iron deficiency, iron malabsorption, and iron loss from both diarrheal disease and intestinal parasites in earlier human populations. This iron-deficiency-anemia hypothesis is inconsistent with recent hematological research that shows iron deficiency per se cannot sustain the massive red blood cell production that causes the marrow expansion responsible for these lesions. Several lines of evidence suggest that the accelerated loss and compensatory over-production of red blood cells seen in hemolytic and megaloblastic anemias is the most likely proximate cause of porotic hyperostosis. Although cranial vault and orbital roof porosities are sometimes conflated under the term porotic hyperostosis, paleopathological and clinical evidence suggests they often have different etiologies. Reconsidering the etiology of these skeletal conditions has important implications for current interpretations of malnutrition and infectious disease in earlier human populations.

Thermal performance and embodied energy analysis of a passive house – Case study of vault roof mud-house in India

This paper investigates thermal performance of an existing eco-friendly and low embodied energy vault roof passive house (or mud-house) located at Solar Energy Park of IIT Delhi, New Delhi (India). Based on embodied energy analysis, the energy payback time for the mud-house was determined as 18 years. The embodied energy per unit floor area of R.C.C. building (3702.3 MJ/m 2) is quiet high as compared to the mud-house (2298.8 MJ/m 2). The mud-house has three rooms with inverted U-shape roof and remaining three rooms with dome shape roof. A thermal model of the house consisting of six interconnected rooms was developed based on energy balance equations which were solved by using fourth order Runge Kutta numerical method. The predicted six room air temperatures were found in good agreement with the experimental observed data on hourly basis in each month for one year. The annual heating and cooling energy saving potential of the mud-house was determined as 1481 kW h/year and 1813 kW h/year respectively for New Delhi composite climate. The total mitigation of CO 2 emissions due to both heating and cooling energy saving potential was determined as 5.2 metric tons/year. The annual carbon credit potential of mud-house was determined as € 52/year. Similar results were obtained for the different climatic locations in India.

Performance evaluation and life cycle cost analysis of earth to air heat exchanger integrated with adobe building for New Delhi composite climate

This paper aims to develop thermal model of a vault roof building integrated with earth to air heat exchanger (EAHE). The building under consideration is made of brick vault and adobe (or mud) structures. The methodology adopted for developing thermal model of this building with six interconnected rooms is presented in this paper. The energy balance equations were solved simultaneously using fourth order Runge–Kutta numerical technique. The results from the thermal model were validated using experimental observed data. Experimental results showed that the room air temperature during winter was found 5–15 °C higher as compared to ambient air temperature while lower during summer months. The results show that annual energy saving potential of the building before and after integration of EAHE were 4946 kWh/year and 10321 kWh/year respectively. The seasonal energy efficiency ratio (SEER) for EAHE was determined as 2–3. This considerable increase in annual energy savings potential of building due to EAHE leads to mitigation of CO 2 emissions about 16 tons/year and the corresponding annual carbon credit of building was estimated as € 340/year. The life cycle cost (LCC) analysis shows that the payback period is less than 2 years for the investment on EAHE system.

Optimized Design of a Steel-Glass Parabolic Vault Using Evolutionary Multi-Objective Algorithms

The paper explores the possibilities offered by evolutionary multi-objective algorithms in structural design. The developed procedure includes the parameterization of a 3D structure, the automatic generation of a finite element (FE) model, and the optimum design. The search of the optimum solution is dealt with using two commercial software packages: Straus7, for FE analysis, and modeFrontier, for optimal search, interlinked by a program purposely developed ( SCU, system control unit). The optimum design of a structure needs a different approach with respect to the traditional design. The paper presents a possible approach and describes more in detail the data pre and post processing including the choice of the solutions on the Pareto's front. A case study, a steel-glass vault roof built in Badenweiler (Germany), is used to demonstrate the effectiveness of the proposed approach. A significant economical saving can be achieved when the optimum design solution is used. The proposed algorithm can then be employed as a useful tool to help the designer in the complex design process.

Design Factors Affecting the Flow of Water through Below-Ground Concrete Vaults

Underground concrete vaults have been and are planned to be used to store contaminated materials, such as hazardous materials and radioactive waste, over long periods of time. To protect humans from exposure to the contamination, the key to this long-term storage is immobilization achieved through designing concrete vaults with enhanced hydraulic performance. This paper evaluates concrete vault design parameters including properties of soil layers surrounding the vault, vault size, slope of the vault roof, and the amount of concrete degradation under various infiltration rates. A numerical model that estimates the flow of water through the vault is used as the computer simulation tool. Conclusions from the modeling simulations are that clay layers, including sand and loam layers forming a capillary barrier and placed adjacent to the vault concrete, were found to have a better hydraulic performance. Smaller vault sizes result in lower seepage through the vault and suggest a scale effect. Roof slope has a relatively small influence on hydraulic performance.

Performance of Building Roofs in the 2003 Bam, Iran, Earthquake

Roofs covering buildings in the city of Bam, Iran prior to the earthquake of 26 December 2003 can be categorized into three main groups: traditional masonry dome or vault, steel I-beam jack-arch system, and concrete beam-hollow block system. The collapse of nonengineered masonry roofs and floor slabs during the earthquake was the single largest contributor to the large number of fatalities. This paper discusses the seismic performance of each type of roofing and their strengths and weaknesses. The poor seismic performance of traditional domes and vault roofs and unanchored jack-arch slabs are noted and the seismic merits of the anchored jack-arch slabs and concrete beam-hollow block slabs are discussed.