Cylindrical Shell Roofs Research Articles

Design and Analysis of Prestressed Shell Roof Structures

Abstract: In this paper, pre-stressed precast substantial Shell roof structures is proposed as an option in contrast to customary roof structures. plan of shell roof top utilizing supported concrete is extremely challenging. To oppose the high strain in base harmony, the substantial support should be pre-stressed. Here, the displaying of various setups of prestressed precast substantial shell roof structures is finished utilizing Staadpro v8i programming by changing its mathematical boundaries, for example, shapes, slant, length and dispersing of the support and investigation and streamlining is done to find the best and best prestressed precast substantial Shell roof structures designs fit to different circumstances feasible way of life implies reconsidering our approaches to everyday life, how we purchase and how we sort out our day to day existence. It is likewise about modifying how we mingle, trade, share, instruct and construct personalities. It implies changing our social orders and living in agreement with our common habitat. As residents, at home and at work, a large number of our decisions - on energy use, transport, food, waste, correspondence and fortitude - contribute towards building economical ways of life In India, customary practices that are feasible and climate well-disposed keep on being a piece of individuals' lives. India has a past filled with low carbon impression and way of life. These should be energized, rather than supplanted by more current yet unreasonable practices and advancements. This is likewise relevant to other non-industrial nations where there is a developing interest in elective models of advancement, and on restoring green cognizance drawing on conventional societies. Keywords: Precast Concrete, RCC cylindrical shell roof structures, STAAD PRO V8i, Prestressed precast shell structures

Evaluation of Load Factor to Be Applied in Buckling Design of Cylindrical Lattice Shells Under Asymmetric Snow Load

The load factor is one of the keys in anti-buckling design for safety together for construction cost, and studies have been becoming demanded in a recent situation that super large and super light spatial structures have been constructed. This paper investigates the relationship between reliability index β and snow load factor γs for anti-buckling design of a simply supported cylindrical lattice shell roof under simultaneous action of both dead load and asymmetric snow load. The cylindrical lattice shell analyzed is composed of an equilateral triangle grid of which members are of steel circular hollow sections. Members are connected rigidly to nodes at their both ends. The snow distribution as a main target is assumed in a way that the snow depth on the half of the arch-like roof is half of the amount on the other half roof. The snow fall depth is here assumed 50cm evaluated as 100-year return period, and its probability is assumed as Gumbel distribution with 100-year reference period. The probability distribution of buckling strength Pcr including geometrical and material nonlinearities is approximately evaluated based on a first-order perturbation. The reliability is calculated based on AFOSM, and the relationship in a form of β to γs is finally expressed for design use.

POD Analysis for modeling wind pressures and wind effects of a cylindrical shell roof

This paper presents a study on the effectiveness of the proper orthogonal decomposition (POD) technique for reconstruction of wind pressure field as applied to a cylindrical shell roof based on simultaneously measured wind pressure data. The influence of wind loading mode truncation on the statistics of dynamic pressures and wind load effects are investigated. The results showed that truncation of higher wind loading modes can have more noticeable influence on the maximum and minimum pressures that the standard derivation (STD) values. The truncation primarily affects the high-frequency content of the pressures. Estimation of background response using wind loading modes is more effective than the use of traditional structural modal analysis.

Strain-Based Finite Element Analysis of Stiffened Cylindrical Shell Roof

A new triangular cylindrical shell finite element is used to obtain an elastic linear analysis of a cylindrical shell roof. The element’s displacement fields are in terms of curvilinear coordinates, satisfy the exact requirement of rigid body modes of deformation and have five degrees of freedom at each of the three corner nodes. The efficiency of the developed element is first tested and then applied to analyze stiffened cylindrical shell roof. The results of the displacement and stress resultant along the stiffener are presented and a parametric study is carried out to find the effect of the varying geometry of the stiffener and the effect of axis rotation of the beam on the level of the internal forces.

Progressive Failure Analysis of Laminated Composite Cylindrical Shell Roofs

A progressive failure analysis of laminated composite cylindrical roofs under transverse uniformly distributed static loadings has been carried out in the present paper using the finite element method. In the finite element analysis, an eight-noded isoparametric shell elements are taken up. The first-ply failure load and the ultimate ply failure load are evaluated and compared using different stress-based failure criteria. The effect of orientation of fibers in a lamina, stacking sequence, and varying boundary conditions, on the strength of the laminate is carried out. Factors of safety and load factors are suggested based on the values of first and ultimate ply failure loads. The damage progression using the failure criterion corresponding to the first-ply failure load has been shown. The areas of damage are correlated with deflection values through explicit equations so as to get an idea about the damage extents without going into elaborate testing. The results are interpreted from practical engineering standpoint to extract meaningful conclusions.

Mechanical Behavior of Single-Layer Two-Way Grid Cylindrical Latticed Shell with Out-of-Plane Tension Members

Single layer two-way grid shell with in-plane and out-of-plane tension members is a new type of single-layer latticed shell roof. This study treats the effects of tension member installation on the buckling load and strength of a single layer two-way grid cylindrical shell roof by the numerical method. The tension members are installed to stiffen the rigidity of a single layer two-way grid shell roof and improve its stability behavior. Tension member installation and placement pattern is focused as both diagonal members of two-way grids and out-of-plane stiffened members in a cylindrical surface. The diagonal member and the out-of-plane member are used to increase the in-plane and the out-of-plane rigidity of a single layer two-way grid shell, respectively. The tension member placement pattern, the load distribution patterns, the initial imperfections and the initial axial force are considered for the numerical calculation parameters. It is confirmed by the numerical analysis that the tension members in out-of-plane and diagonals caused the increase in the buckling and strength of two-way grid shell.

Application of the duality in the finite element analysis of shell: self-dual metis planar shell elements

In this paper, an application of the duality principle in finite element shell analysis is presented. It is based upon Lure (Prikl. Mat. Mekh, XIV 5, 1958) and Goldenveizer's (Theory of thin shells, Pergamon Press, 1961) theory of thin shells. For the finite element analysis of thin shells, using the stress function, the problem of finding a stress fields in equilibrium and expressing their continuity across the interfaces is shown to be identical to the problem of derivation of conforming displacement fields and vice versa. It appears that one may derive from this concept of duality a new family of shell finite elements: the auto-dual shell elements. In this paper, we consider a self-dual flat element for thin shell analysis. This element is based on the already developed and implemented in LTAS department, University of Liège. It was mixed hybrid elements called ‘mixed métis’. Numerical efficiency is demonstrated by means of some examples: cylindrical shell roof simply supported by two diaphragms and submitted to its dead weight and cylinder loaded by two diametrically opposed point loads, clamped hyperbolic shell loaded by uniform normal pressure.

連続体置換および並列多質点系モデルを用いた単層円筒ラチス屋根構造物の地震応答評価に関する研究

In this paper, an alternative evaluation procedure of seismic responses using the continuum shell analogy and analogical lamped mass model has been proposed. Then, the linear time history response analyses for various input earthquake waves have been carried out. The adopted analytical parameters are of the open angle of cylindrical shell, the margin of safety ratio of roof members and the horizontal resistance of sub-structure. Also, the sectional area of roof members has been designed by dead load. As the result, it is proposed that the maximum response acceleration and displacement can be evaluated by using the present evaluation method even if the higher-mode vibrations are predominated. Based on these, it is suggested that the present simple evaluation method would be useful for seismic design for single layer cylindrical latticed shell roof structures.

固定荷重で断面算定された単層円筒ラチス屋根の非線形座屈性状と弾性座屈耐力

In this paper, the complex nonlinear buckling behaviors of pressurized latticed cylindrical shell roofs affected by geometrical initial imperfections have been investigated. The sectional area of roof members of the adopted latticed cylindrical shell has been designed by dead load. Then the nonlinear numerical experiments for various imperfection amplitudes and modes have been analyzed. Also a simply calculated buckling loads based upon the continuum shell analogy has been represented. This simple design procedure would be useful for the design of linear buckling loads for single layer cylindrical latticed roofs.

Analysis and Design of Concrete Cylindrical Shell Roof Structure

Combined with the roof of a warehouse the arched shell roof structure is select, simulation Numerical simulation is carried out for the arched shell roof structure system by the ANSYS finite element method, the deformation and stress are obtained which meet the specification requirements. So it is reasonable to select the thin vaulted roof. Finally, the arrangements of the two prestressing tendons of prestressed concrete beams in the framework and the matter which needs to be paid attention to during designing are given, and these can provide reference for similar finite element solution and design of the structural system.

Buckling Load Evaluation Method for Single Layer Cylindrical Lattice Shells

A rational design evaluation procedure is investigated for the elastic overall buckling load carrying capacity of single layer cylindrical lattice shell roof structures. The nature of the imperfection sensitivity of these structures is for the first time reviewed in this paper. This allows the development of the reduced stiffness buckling analytical concept for the lattice shells based upon the introduction of a simple lower bound estimation equation through the use of the so-called continuum shell analogy theory. The linear and nonlinear buckling loads found from conventional finite element analyses are compared with the present estimations. Finally, the elastic-plastic load carrying capacity estimation method through the use of the present elastic lower bound criteria is also proposed.

RESPONSE EVALUATION OF HIGH-RISE CYLINDRICAL LATTICE SHELL ROOFS WITH SUPPORTING SUBSTRUCTURES

Seismic response of cylindrical lattice shell roofs are known to be affected by its rise and supporting substructures. The authors have proposed simple method for estimating response of such shell roofs using amplification factors, however, that does not cover high-rise shell roofs.In this paper, simple response evaluation method for lattice shell roofs with high-rise proportions supported by various stiffness of substructures is proposed using continuous approach as the previous studies including those for high-rise domes, and their validities are discussed against response spectrum analyses based on CQC method.

STUDIES OF THE BUCKLING MODE FOR THE ELASTIC BUCKLING LOAD ESTIMATION OF SINGLE LAYER LATTICED CYLINDRICAL ROOFS

In this paper, the complex nonlinear buckling behaviors of pressurized latticed cylindrical shell roofs affected by initial imperfections have been represented. These nonlinear numerical experiments for various imperfection amplitudes and modes have precisely been analyzed on account for the agreements between the buckling modes at the lower bound to these associated scattering buckling loads and an alternative simple calculation value of modes based upon the continuum shell analogy. This simple approach using the continuum shell analogy would be useful for the actual buckling design of single layer cylindrical latticed roofs.

VIBRATION TESTS OF CYLINDRICAL LATTICE SHELL ROOFS SUBJECTED TO EARTHQUAKE MOTIONS WITH ARBITRARY DIRECTION

Seismic response of cylindrical lattice shell roofs with supporting substructures is known to be amplified in vertical direction even under horizontal input, and their amplitude changes along the direction of earthquake motion. However, the seismic response behavior under the inputs in arbitrary direction has not been sufficiently investigated. In this paper, seismic vibration tests are carried out using small scale models with supporting substructure in order to make clear the effects of difference of input direction and relationship between mechanical properties of roofs and substructures on response behavior of shell roofs. It is confirmed that the simple response evaluation methods proposed in previous papers apply to the responses subjected to earthquake motions with arbitrary direction.

Nonlinear Finite Element Analysis of Ferro-cement Slabs and Shell Roofs

The present work involves developing an analytical model to study the behavior of ferro-cement slabs and shell roofs, and to adopt the most realable constitutive relationships for the mortar material to predict the nonlinear response of ferro-cement roofs by using the finite element method. To represent the mortar and wire mesh, a layered approach is used. Mortar is considered as a strain-hardening material and exhibiting strain-hardening behavior till it reaches the peak stress, beyond which, mortar enters the descending portion (strain softening) until it reaches the crushing strain. Tension stiffening is used to model the post- cracking tensile strength of the mortar. Under further loading in post-cracking stage shear retention is used to model the shear transfer throughout the cracks. The behavior of steel reinforcement and wire mesh is considered as elastic perfectly plastic with linear strain hardening. The predicted results of ferro-cement slab and cylindrical shell roofs had shown a good agreement with the published experimental results.

屋根形円筒シェルの線形振動理論の定式化

The vibration theory of cylindrical shells can be found in Flugge's book, also many papers have been published. However, most of these papers are not on the roof type but on the closed shape, excepting a few, such as Heki's approximate theory and Kunieda's exact but abridged expression of very tedious calculation caused by the singularity problems. So, to avoid those problems, using the potential function and introducing smoothly varying solutions, the exact theory for cylindrical shell roofs is formulated in Fourier series developed in longitudinal direction, and the lists of formulas for necessary quantities are presented in common forms.

鉛直方向に支持された裾梁を有する円筒シェル屋根の線材化理論とその解析

The failure mechanism and ultimate strength of a cylindrical shell roof with vertically supported edge beams are evaluated by stress resultants based on elastic analysis. It is not easy job to analyze the cylindrical shell roof with analytical procedures. Because it is a hard work to analyze cylindrical shell equations. We assume displacement modes of the cylindrical shell in circumferential directions. Applying the modes to the functional of the roof, we evaluate the functional that enables us to get the ordinary differential equations of motion of the system. Adopting the procedure, we analyze the cylindrical shell roof models and show displacements and stress resultants of static behavior, which are compared with the values obtained by analytical procedures. The procedure lets us to get natural frequencies of the roof.

On the membrane locking of h–p finite elements in a cylindrical shell problem

AbstractWe study the performance of high‐order h–p finite clement schemes in approximating the nearly inexlensional deformation state of a thin cylindrical shell roof with both ends free. Severe locking is demonstrated for both quadratic and cubic elements, and even for higher order if the grid is not aligned with the axis of the cylinder.Carefully designed selective reduced integration is shown to improve the accuracy of the finite element approximation at low and moderately high orders. However, so far this technique seems to work well only on aligned grids.

水平梁を有する鉄筋コンクリート造円筒シェル屋根の終局耐力 : 直交異方性円筒シェル屋根の解析と終局耐力評価式

This paper presents an evaluating procedure of ultimate strength of reinforced concrete cylindrical shell roofs with vertically supported edge beams. Differential equations of the roof with orthtropic materials are analyzed by applying the Galerkin's method. And, it is shown that stress resultants of the roof are few affected by a variation of Young's modulus of the shell. This let us evaluate the stress resultants after occuring concrete cracking on the shell. Then, an procedure that evaluates ultimate strength of three typical failure mechanism of the reinforced concrete cylindrical shell roof is shown and is examined by comparing with experimental study.

Calculation for cylindrical shell under local vertical loadings

In this paper, we use the method of mixed-type series to derive the analytical solutions of cylindrical shell, which is simply supported along the transverse edges and subjected to the local vertical loads, and give the analytical expressions of the solutions for this kind of shell under five types of local vertical loading. A numerical example for a cylindrical shell roof, which is simply supported along the transverse edges and is free along the longitudinal edges, is given in this paper and from the calculated results it may be seen that the convergence of the solutions is considerably satisfactory. Using the solutions of this paper, we can deal with some practical problems of underground structure.