Basement Roof Research Articles

Experimental and simulation study on seismic performance of the new beam-column transfer joint as the embedded part of the basement roof

A new beam-column transfer joint is proposed, which consists of an upper column with a concrete-filled steel tube column (CFST), a lower column with a variable-diameter steel-concrete column (SRC), and a reinforced concrete beam. The new transfer joint is mainly set on the roof of the basement of a high-rise building structure. Compared with traditional transfer joints, it reduces the amount of steel used, increases the use space of the basement, and improves the seismic performance of the structure. New transfer joint and traditional joint were tested under cyclic loading to investigate response of the proposed joint. The main performance indicators studied are hysteretic response, energy dissipation, ductility, and stiffness degradation. Research results show that the energy consumption and carrying capacity of the new transfer joint are higher than those of the traditional joint. The correctness of the finite element analysis was verified through the test results, and a parametric analysis was carried out on this basis. It was found that the diameter reduction position of the steel tube and the length of the corbels of the lower column have little impact on the seismic performance of the new transfer joint. The thickness of the steel tube has a greater impact on the seismic performance of the new transfer joints. The peak bearing capacity is increased by about 17 %. Finally, according to the formula given by the specification, the embedding effect of the new transfer joint and the traditional joints are compared. The effect of the new transfer joints is better than that of the traditional one, which can provide a reference for future basement design of high-rise building structures.

Semi-reverse Construction Technology Combined with Basement Roof and Support System

Semi-reverse Construction Technology Combined with Basement Roof and Support System

Comparative Analysis of Mechanical Performance of Flat Slabs with Reverse and Conventional Column Caps

Compared with the conventional column caps, the reverse column caps that are used for slab-column joint of basement roof can improve the clearance of the basement while ensuring structural safety, and they are hidden in the covering soil without affecting the appearance and use of upper surface of flat slabs. In this paper, four finite element models, which are loaded by column-end displacement-control mechanism, are established. These models are used to investigate the mechanical performance of slab-column joint for flat slabs with reverse and conventional column caps. The obtained numerical results were thoroughly analysed, indicating that the load-carrying capacity performances of flat slabs with conventional column caps are much higher than their counterparts with reverse column caps, but flat slabs with conventional column caps possess lower mechanical ductility. Moreover, the reverse column caps were found to exhibit a severe damage at ultimate load; therefore, transverse stirrups were distributed into the reverse and conventional column caps for the purpose of comparison. The comparison results revealed that the ultimate load of the slab-column joints with reverse column cap can be increased by 2.4% by arranging transverse stirrups in column cap, but the ductility is decreased by 13.4%. For the slab-column joints with conventional column cap, the ultimate load is decreased by 10.0% and the ductility is decreased by 1.6% when transverse stirrups are arranged in column cap. Therefore, arrangement of transverse stirrups in column cap should be determined based on the actual situation in the flat slab system with reverse column cap, and it is not recommended to arrange transverse stirrups in column cap in the flat slab system with conventional column cap.

Design of Heavy-duty Transfer Steel Platform Based on Finite Element Method

In order to effectively solve the problems of high cracking risk, high safety risk, large construction period impact and high engineering cost of the basement roof of the scaffolding heavy-duty conversion platform, a construction method of heavy-duty conversion steel platform was proposed by referring to the force principle of the above-ground frame structure. The force mechanism, construction process, operation points and quality assurance measures of this method are clarified by theoretical analysis method combined with on-site engineering practice. Finally, the construction method of heavy-duty conversion steel platform is clarified by comparing with the traditional construction method of scaffolding support and reinforcement. The advantages. The research results show that the heavy-duty conversion steel platform mainly transfers the upper heavy lifting load to the steel beam through the subgrade box, and then transmits it to the pile foundation through the steel beam; It is green and environmentally friendly, and can effectively solve the quality and safety problems of underground structures. Compared with the traditional full-house scaffolding support and reinforcement construction method, the cost saving rate of the optimized heavy-duty conversion steel platform reinforcement method is about 12%, which is worthy of further promotion and application.

Design features and best practice in podium deck waterproofing : Examples and perspectives from UK industry

Podium decks — a basement roof at, or around, ground level which is not covered by superstructure — are an increasingly common feature in the modern built environment. This increase may be partly attributed to growing awareness of the need for sustainability. Green roofs, sustainable urban drainage, water attenuation and even parks and farms are being located on top of podium decks. Waterproofing of these podium decks is vital in order to use the space created beneath and also to prolong the life expectancy of the structure. This research analyses the available best practice guidance and then compares the key waterproofing design features with opinions from industry. Opinions are gathered first through 78 questionnaire respondents and then interviews with four experienced respondents with unusual views. These findings are then compared with case studies of podium decks with waterproofing failures. This research suggests that robust podium deck waterproofing design comes from the following choices in the fundamental features of waterproofing design for podium decks: a) reinforced concrete structural deck; b) fully bonded waterproofing membrane; c) waterproofing laid to a gradient to falls; and d) provision of a drainage void over the waterproofing layer. As a result of these findings, this paper calls for more authoritative best practice guidance on podium deck waterproofing design in a bid to reduce pressures in procurement that lead to weaker waterproofing design choices. This research may be of interest to built environment professionals because it identifies some fundamental features of podium deck waterproofing design and clarifies which design choices are perceived to deliver more robust waterproofing than others.

Analysis of temperature stress of roof of super-long basement

In this paper with a practical project as an example of super-long basement, using structural analysis software MIDAS/Gen (2014) Chinese version, through the analysis of the temperature effect of indirect effect, analyze the super-long basement roof temperature stress of concrete structure, calculation of super-long structure under temperature influence of temperature stress, and according to the temperature stress calculation reinforcement, and the structure of the combination of action effects, to solve the temperature stress generated in the basement of super long concrete structure.

Development and seismic performance of staggered and out-of-plane joints between concrete-filled steel tubular column and reinforced concrete beam

This article presents a staggered and out-of-plane connection between concrete-filled steel tubular column and reinforced concrete beam (SOC-TCB). SOC-TCB is taken from the basement roof joint of Suning center, which is a height of 341.85 m in China. In this joint system, the H-shaped steel brackets are welded with steel tube to transfer shear and moment. Moreover, the reinforcing bars are interrupted by steel tube and lapped with steel bracket. To investigate the seismic behavior of SOC-TCB, four types of SOC-TCBs were tested under reversal cyclic loading. The differences between specimens were staggered height and out-of-plane angle. Seismic performance was evaluated based on hysteretic behavior, failure mode, shear deformation, rotational deformation, and energy dissipation. The results showed that the shear deformation of joints was extremely small and the plastic hinges were formed at reinforced concrete beams. Due to insufficient anchorage length of longitudinal bars, anchoring failure was found in the reinforced concrete beams. However, SOC-TCB showed better seismic behavior as long as sufficient anchorage of longitudinal bars was ensured.

THREE-DIMENSIONAL GIS MODELING OF THE STRELTSOVSKAYA CALDERA’S COVER ON THE BASIS OF SURFACE RELIEF AND THE BASEMENT’S TOP DIGITAL MODELS

Based on the consideration and analysis of different approaches to obtaining data for constructing a digital elevation model and types of three-dimensional surface representation, the choice of the most optimum technique for construction and visualization of three- dimensional model of the volcano-sedimentary cover of the Streltsovskaya caldera in Eastern Transbaikalia has been substantiated. The creation of such model determines the need for detection, identification and monitoring of processes, phenomena and factors of natural and anthropogenic origin at uranium deposits of the same named ore field, which are developed by underground way in difficult mining and geological conditions. To solve this problem, modeling of the daylight surface relief and the basement roof has been carried out on the basis on remote sensing data, geophysical studies, cartographic materials vectorization and processing results. The space between the constructed surfaces due to the algorithm for creating closed framework of surfaces has been transformed into a new object representing three-dimensional volumetric model of the caldera volcano-sedimentary cover. The received results allow creating a predictive model of the tectonic and dynamic state of the Streltsovky ore field rock massifs for the deposits development and mine workings design.

Prospects of Oil-and-Gas Contents from the Paleozoic in the Southern Flank of the Voronezh Anteclise by Analyzing Data of Recent Regional Seismic Surveys

Based on the materials of regional seismic surveys, general structural maps of the basement roof and the carbonate stratum, as well as a map of the carbonate formation isopachytes, are plotted. Using statistical methods, the trend-component for the basement roof is determined and the map of isolines characterizing the II-order structural-tectonic elements is obtained.

Fold deformations of the paleozoic basement roof in the Chunkurchak Trough, Kyrgyz Ala-Too Range

A structural–geological study has been performed on the northern slope of the Kyrgyz Ala-Too Range. Deformations of the peneplaned Paleozoic basement surface, structures of granite disintegration, and morphostructural manifestation of Late Cenozoic tectonic movements have been investigated. Based on the location of pre-Paleocene peneplain remnants with the retained weathering mantle partly overlapped by Paleocene–Miocene sedimentary complexes, we have reconstructed the morphology of the folded surface of the Chunkurchak Trough separated from the Chu Basin at the early Miocene. The dome–fold forms, the morphology and arrangement of which are controlled by disintegration of the basement, have been described for the basement surface. It has been established that granites are broken by systems of steeply dipping, fanshaped, and gently dipping faults and fractures. Variously oriented insignificant offsets along slickensides, as well as displacements deduced from the geometry of fracture intersections, are a result of volumetric cataclastic flow of rocks. The tectonic mobility of disintegrated granites, which are abundant in the Paleozoic–Precambrian basement, explains the complexity and scale of tectonic processes initiated by Cenozoic activation. In paleotectonic reconstructions, which take into consideration tectonic flow and the redistribution of basement masses, the estimates of Cenozoic relative rapprochement of the Chu Basin and the Kyrgyz Ala-Too Range decrease substantially to 4–6 km.

Retraction Notice: Study on Direct Waterproof Construction of Basement Roof in Planting Area

Retraction Notice: Study on Direct Waterproof Construction of Basement Roof in Planting Area

浅谈高层建筑结构嵌固端位置的选择

在实际工程设计中，多数结构工程设计人员并未重视高层建筑结构嵌固端的选择。这样往往会造成材料浪费，也会给高层建筑结构留下隐患。对于高层建筑结构嵌固端的定义，部分结构设计人员也存在误区，认为是力学嵌固，其实应为强度嵌固。规范对地下一层顶板作为嵌固端明确了要求。本文对三种地下室平面面积型式不同的高层建筑结构嵌固端做了初步的探讨，得出了一般情况下，不同地下室平面型式嵌固端的位置，并得出了地上一层与相关范围地下一层侧向刚度比是衡量地下一层顶板能否作为高层建筑结构嵌固端的关键。 In the practical engineering design, structural engineering staffs did not attach importance to fixed end of high-rise building structure. This will cause material waste, and will also leave hidden troubles to the high-rise building structure. Some of the structural designers have mistakes in the definition of fixed end of the tall building, who regard them as mechanics embedment, but in fact it should be strength-mounted. Specification makes requirements clearly about the roof of the underground layer as embedding end. In this paper, three basement flat area types of high-rise building structure embedded end have been studied. It comes to conclusions 1) there are different embedding positions in different basement flat forms under normal circumstances, and 2) the lateral stiffness ratio of ground floor with the relevant range of underground floor is the key to measure whether the basement roof can be used as a high-rise building structure embedded fixed end.

Oil and gas pools in weathering crusts on the sedimentary basin basement

Weathering crusts of the sedimentary basin basement are collectors in several regions of the world. They enclose huge reserves of oil and gas. The paper considers the geochemical, mineral, and petrophysical heterogeneities of weathering crusts that should be taken into consideration in the prospecting, exploration, and development of hydrocarbon raw material therein. Areal and linear-fissure types of weathering crust are defined. They were formed before the overlapping of basement by rocks of the sedimentary cover. Areal crusts are pervasive at the basement roof, whereas linear-fissure crusts are formed along fractures. A complete weathering crust profile includes the following zones (from the bottom to top): disintegration, leaching and hydration, hydrolysis, and final hydrolysis. Rocks of the lower two zones represent the cavernous-fissure collector, while rocks of the upper zones are impermeable. In the arches of uplifted blocks of the basement, weathering crusts are subjected to erosion during marine transgressions. In such places, the roof is composed of rocks of the lower permeable zones that often make up a single heterogeneous natural reservoir overlapped by sandy collectors of sedimentary sequences. Linear-fissure weathering crusts show zonal distribution with good filtration-capacity properties. Several large oil and gas pools have been discovered in them.

Main Features of Kuril-Kamchatka Deep-Sea Trench Tectonics and Geologic Development: ABSTRACT

The upper crust structure of the Kuril-Kamchatka deep-sea trench and continental slope is a system of horst-anticlinorial uplifts of the acoustic basement and separating them partially are compensated graben-synclinorial troughs stretching in the northeastern direction according to the trench general trend. From dredging data the acoustic basement rock associations of the horst-anticlinorial uplifts of the trench continental slope are pre-Neogene (Late Cretaceous and older) complexes of the deformed geosynclinal volcanogenic and sedimentary deposits broken by gabbroids, granodiorites, and granitoids. Graben-synclinal troughs are filled with sedimentary deposits mainly of the Neogene-Quaternary ages, the thickness of which in some basins exceeds 1.8 mi (3 km). The oceanic slope of the trench is composed of the sedimentary End_Page 968------------------------------ layer with thickness of about 300 to 990 ft (100 to 300 m), lying on the second layer of the oceanic crust. According to the dredging, the acoustic basement roof on the marginal oceanic swell (Hokkaido Rise) is mainly composed of metamorphosed basalts and it seems to include the sedimentary rock intercalation. From the whole rock K-Ar data, the period of intensive basaltic volcanism on the Hokkaido Rise is from Cretaceous to Paleogene. Crustal faults along the Kuril-Kamchatka and Aleutian trenches can be characterized as normal faults, especially for the oceanic side, which points out their development in crustal tension conditions. The faults transversal to the trenches are mainly established from magnetic data. The anomalous magnetic field is subdivided generally in two regions in which the trend of anomalies varies from the subparallel (in the southern part of trench) to the subtransversal to the trench (in the northern part). A vast region next to the oceanic plate adjacent to the crustal and northeast parts of the Kuril-Kamchatka trench is characterized by the absence of linear magnetic anomalies which can be associated with the structure and movement of the subducted plate. End_of_Article - Last_Page 969------------