227 research outputs found
Joint Layout Design: Finding the Strongest Connections within Segmental Masonry Arched Forms
Full text linkSegmental arched forms composed of discrete units are among the most common construction systems, ranging from historic masonry vaults to contemporary precast concrete shells. Simple fabrication, transport, and assembly have particularly made these structural systems convenient choices to construct infrastructures such as bridges in challenging environmental conditions. The most important drawback of segmental vaults is basically the poor mechanical behaviour at the joints connecting their constituent segments. The influence of the joint shape and location on structural performances has been widely explored in the literature, including studies on different stereotomy, bond patterns, and interlocking joint shapes. To date, however, a few methods have been developed to design optimal joint layouts, but they are limited to extremely limited geometric parameters and material properties. To remedy this, this paper presents a novel method to design the strongest joint layout in 2D arched structures while allowing joints to take on a range of diverse shapes. To do so, a masonry arched form is represented as a layout of potential joints, and the optimization problems developed based on the two plastic methods of classic limit analysis and discontinuity layout optimization find the joint layout that corresponds to the maximum load-bearing capacity
The role of different sliding resistances in limit analysis of hemispherical masonry domes
Full text linkA limit analysis method for masonry domes composed of interlocking blocks with non-isotropic sliding resistance is under development. This paper reports the first two steps of that work. It first introduces a revision to an existing limit analysis approach using the membrane theory to find the minimum thickness of a hemispherical dome under its own weight and composed of conventional blocks with finite isotropic friction. The coordinates of an initial axisymmetric membrane surface are the optimization variables. During the optimization, the membrane satisfies the equilibrium conditions and meets the sliding constraints where intersects the block interfaces. The results of the revised procedure are compared to those obtained by other approaches finding the thinnest dome. A heuristic method using convex contact model is then introduced to find the sliding resistance of the corrugated interlocking interfaces. Sliding of such interfaces is constrained by the Coulomb’s friction law and by the shear resistance of the locks keeping the blocks together along two orthogonal directions. The role of these two different sliding resistances is discussed and the heuristic method is applied to the revised limit analysis method
Structurally informed design of interlocking block assemblages using limit analysis
No full textThis paper presents a computational framework to design assemblages of interlocking blocks and to analyze their structural feasibility. The core of this framework is an extension of limit analysis to corrugated interfaces with orthotropic sliding behavior. Such block interfaces are made of a number of locks (i.e. projections on the corrugated faces, locking the blocks together) with rectangular cross section. The sliding resistance at the block interfaces is governed by the shear resistance of the locks and Coulomb’s friction law, normal to and along the locks, respectively. This resistance is assumed as a function of different interface geometric parameters and the stress state on an interface is represented by using a number of contact points distributed over the lock centerlines. The abstraction model has been validated through the comparison of the torsion–shear behavior of an interface obtained by the proposed model and experimental tests reported in the literature. The extended limit analysis has been implemented to model single-layer shells. When the model is infeasible, the geometry of the overall shell, blocks, and interlocking interfaces can be adjusted by the designer to make the model structurally feasible. The performance of the framework is presented through several examples, which demonstrate the relationships between the geometry of the interlocking interfaces and the stability of the assemblages
A HEURISTIC METHOD FOR MODELLING THE SLIDING RESISTANCE OF MASONRY ASSEMBLAGES OF INTERLOCKING BLOCKS
No full textThere is a wealth of recent literature dealing with the significant role played by friction in the seismic response of conventional masonry structures. Within this framework, a crafty improvement of such structures is represented by interlocking masonry structures made by interlocking blocks that enhance the sliding resistance at block interfaces. In fact, these are rigid block units which, on their faces, have a number of locks keeping the blocks together and preventing sliding. Such typologies of blocks can increase the structural functionality of an assemblage during and after the construction. The interlocking interface may have different sliding resistances in different directions, depending on the orientation and the mechanical and geometrical features of the locks. This paper is aimed at finding the sliding resistance of interlocking interfaces with non-isotropic sliding properties. The constraint is a function of geometric and mechanical properties of such interfaces, allowing the use of the convex contact formulation method to analyse the structural behaviour of masonry assemblages composed of interlocking blocks
SiDMACIB - Structurally informed Design of Masonry Assemblages Composed of Interlocking Blocks
No full textHORIZON 2020 Project
MARIE Skłodowska-CURIE Individual Fellowships (IF)
Call: H2020-MSCA-IF-201
ASSEMBLABILITY CONSTRAINTS IN THE LIMIT ANALYSIS OF 3D MASONRY INTERLOCKING BLOCKS
No full textThis paper presents a method to analyses the structural feasibility and assemblability of the masonry assemblages composed of interlocking blocks. Interlocking blocks with projections and depressions on their faces have relatively better structural performance comparing to the conventional blocks with flat faces, during and after the construction. Therefore, they can represent proper alternatives to the conventional blocks for the seismic retrofitting of unreinforced masonry structures. Structural soundness and assemblability of a model are both functions of the interlocking block geometry. The proposed methods enable the designer to adjust the shape of the interlocking blocks, while meeting the structural and assembling requirements. The paper first introduces an extension of the limit analysis to the assemblages with corrugated interlocking interfaces having anisotropic sliding behavior. Then, the work reformulates the extended limit analysis to develop a method to measure the structural infeasibility due to the lack of sliding resistance at the interlocking interfaces. This is called sliding infeasibility and the designer can minimize it during the shape exploration. Finally, an assemblability method is presented to check if the designed interlocking blocks can be assembled on the other blocks in contact. This method is added to the extended limit analysis and the sliding infeasibility measurement method in form of a geometric constraint that prevents modeling of un-assemblable structures
A digital tool to design structurally feasible semi-circular masonry arches composed of interlocking blocks
No full textLimit state approach for structurally informed design of shells composed of interlocking blocks
No full textThis work demonstrates an extension of limit analysis with concave model to design 3D assemblages of dry jointed interlocking rigid blocks with orthotropic sliding resistance. A digital framework is developed to design and analyse the structural feasibility of assemblages of interlocking blocks. The sliding resistance is defined as a function of the geometric properties of the interlocking interface. Adjusting the geometric parameters, designers can modify the infeasible models to be stable. The limit states are governed by two types of failure planes including dry joints and fracture strips between the locks and the main body of the block. These planes are merged and simplified to an orthotropic interface between two blocks. Then, the interface is abstracted to a number of point contact points distributed on lock centrelines, at which the stress resultants are computed by solving the equilibrium problem under proper sliding constraints. Applying this method, the limit conditions for several single layer shells with hexahedral units assembled with stack bond are illustrated
A digital tool to design structurally feasible hemispherical masonry domes composed of interlocking blocks
No full textPushover analysis of the rocking façades of a sample of masonry churches. The role of friction and geometry to identify homogeneous classes of vulnerability for statistical analyses
No full text- …
