Column connection detail, Kangaroo Point House

Hand-made spotted gum column on edge of outdoor room.

Value-based selling of the column connection solution as part of project sales

The objective of this study was to find out how third party influencers can facilitate value-based selling in a network and how suppliers should aim to impact on these third party influencers to facilitate value-based selling. The study considers construction industry, selling the column connection solution and third party influencers. Third party influencers examined in this study were structural designers. The study also aims to find out structural designers’ value drivers and the differences between the market areas that this study related to. The theoretical part of the study focuses on two separate areas. The first part of the theory focuses on a value-based selling concept: what it is, what it requires and what are the main barriers for value-based selling. The second part of the theory examines value creation in networks. The present knowledge over value creation in networks and different network actors are presented. Project marketing is also discussed briefly because this study’s topic, which is highly related to project business. The results reveal structural designers’ value drivers considering the usage of the column connection solution and present ways how suppliers should aim to impact structural designers to facilitate value-based selling. The main result of the study indicates that third party influencers can have a positive impact on facilitating value-based selling. Structural designers are communicating more or less with all the salient actors in different project phases and they can act as sponsors to support the sales of Peikko’s column connection solution and promote solution to other actors involved to the project. This requires that structural designers can understand the actual benefits of how the solution can improve their and their customers’ business.

Performance of 1/3-scale model precast concrete beam-column connections subjected to cyclic inelastic loads : report no. 4 /

Mode of access: Internet.

Buckling of a continuous beam-column on elastic supports.

Sponsored by Column Research Council of Engineering Foundation, Pennsylvania State Highway Department, Bureau of Public Roads.

Punching shear of slab-column connection in flat plate construction

The flat plate system is currently widely used in construction. It permits architectural flexibility, more clear space, less building height, easier formwork, and shorter construction time. However, there remains the problem of brittle punching failure due to the transfer of shearing forces and unbalanced moments at the flat plate-column connection. It is the purpose of this paper to investigate the effects of various interdependent factors that govern the punching shear resistance and behaviour of the flat plate-column connection, as well as their inclusion in current Codes.

Study of a beam-column joint of a precast system by nonlinear numerical analysis

The present work consists of a detailed numerical analysis of a 4-way joint made of a precast column and two partially precast beams. The structure has been previously built and experimentally analyzed through a series of cyclic loads at the Laboratory of Tests on Structures (Laboratorio di Prove su Strutture, La. P. S.) of the University of Bologna. The aim of this work is to design a 3D model of the joint and then apply the techniques of nonlinear finite element analysis (FEA) to computationally reproduce the behavior of the structure under cyclic loads. Once the model has been calibrated to correctly emulate the joint, it is possible to obtain new insights useful to understand and explain the physical phenomena observed in the laboratory and to describe the properties of the structure, such as the cracking patterns, the force-displacement and the moment-curvature relations, as well as the deformations and displacements of the various elements composing the joint.

Behaviour of grouted dowels used in precast concrete connections

This research deals with the behaviour of grouted dowels used in beam-to-column connections in precast concrete structures. The research focuses primarily on the theoretical and experimental analysis of the resistance mechanism of the dowels. The experimental programme included 15 models for analysing the following variations in dowel parameters: a) dowel diameters of 16, 20 and 25 mm, b) dowel inclinations of 0 degrees (i.e. perpendicular to the interface), 45 degrees and 60 degrees, c) compressive strength of classes C35 and C50 for the concrete adjacent to the dowels, and d) the absence or presence of compressive loads normal to the interface. The experimental results indicate that the ultimate capacity and shear stiffness of the inclined dowels are significantly higher than those of the perpendicular dowels. Based on these results, an analytical model is proposed that considers the influence of the parameters studied regarding the capacity of the dowel.

Comportamento de chumbadores embutidos em concreto com fibras de aço para ligações viga-pilar de concreto pré-moldado

O presente trabalho trata do estudo do comportamento de chumbadores grauteados inseridos em concreto com fibras de aço em ligações viga-pilar de estruturas de concreto pré-moldado. Este estudo é importante para se entender e poder quantificar a influência da rigidez deste componente no comportamento de ligações semirrígidas de estruturas de concreto pré-moldado. O objetivo do trabalho é estudar o mecanismo do chumbador no concreto com fibras de aço em ensaios específicos e avaliar também o comportamento de uma ligação viga-pilar de concreto pré-moldado utilizando estas fibras no consolo e no dente da viga. Nesta pesquisa foi realizado um programa experimental no Laboratório de Estruturas da EESC, uma análise numérica com o emprego do software DIANA® e uma comparação com formulações analíticas existentes para o cálculo da força última destes componentes. Foram ensaiados nove modelos experimentais para avaliar especificamente o mecanismo resistente do chumbador, variando-se os diâmetros das barras, sua inclinação e a porcentagem de fibras de aço no concreto. Além destes modelos, foi realizado ensaio de uma ligação viga-pilar de concreto pré-moldado para avaliar a rigidez da ligação com chumbador inserido em concreto com fibras de aço. Nos ensaios experimentais dos chumbadores observou-se que modelos com concreto com fibras de aço apresentam rigidez até 25% maior se comparado ao modelo com concreto convencional. Verificou-se que o graute utilizado para solidarizar os chumbadores exerce significativa influência na capacidade última do modelo, podendo diminuir em cerca de 30% a capacidade de carga. A ligação viga-pilar de concreto pré-moldado utilizando concreto com fibras de aço no consolo e no dente da viga se comportou de maneira satisfatória, não apresentando fissuração na interface dos diferentes concretos. Na comparação dos modelos ensaiados com as formulações teóricas extraídas de trabalhos de referência verificou-se que, para os modelos específicos de chumbador, a formulação existente é representativa. Para a ligação viga-pilar, alguns ajustes na formulação analítica se fizeram necessários para considerações de efeitos de grupo e de borda observados e decorrentes da utilização de dois chumbadores na ligação proposta neste trabalho.

A failure criterion for fillet welds

The work constitutes a study of the strength of mild steel fillet welds subject to static loading, and the behaviour of flange welded beam-column connections under combined bending and shear. Tests are conducted on short welds in the as-welded and stress relieved conditions, and also on full-size beam-column connections. It is shown that welds under compression have a lower strength than when under tension. Failure of the fillet weld is initiated at the weld root, the important factor controlling the initiation being weld ductility. The greater the residual stress, the lower the weld ductility and ultimate strength. Thermal stress relieving increases strength by as much as 30%. Weld failure plane is rarely at the throat and varies from 0° to 45° depending upon loading condition. Failure plane average stresses are related by a circular function which is expressed in terms of externally applied forces at limit state. The tension weld of a flange-welded beam-column connection always fails before the compression weld. The shear load sharing between the welds is a complex function of elastic compression of the web, elastic/plastic deformation of the flanges, load/deformation characteristics, and the type of load application. Bearing forces between the compression flange and column face produce low level bearing stresses and frictional forces which make a negligible contribution to shear load resistance. Three modes of connection failure are possible; 'end mode', 'bending mode' and 'shear mode', with a sudden change taking place between the two latter.

Hybrid mathematical and informational modeling of beam-to-column connections

The analysis of steel and composite frames has traditionally been carried out by idealizing beam-to-column connections as either rigid or pinned. Although some advanced analysis methods have been proposed to account for semi-rigid connections, the performance of these methods strongly depends on the proper modeling of connection behavior. The primary challenge of modeling beam-to-column connections is their inelastic response and continuously varying stiffness, strength, and ductility. In this dissertation, two distinct approaches—mathematical models and informational models—are proposed to account for the complex hysteretic behavior of beam-to-column connections. The performance of the two approaches is examined and is then followed by a discussion of their merits and deficiencies. To capitalize on the merits of both mathematical and informational representations, a new approach, a hybrid modeling framework, is developed and demonstrated through modeling beam-to-column connections. Component-based modeling is a compromise spanning two extremes in the field of mathematical modeling: simplified global models and finite element models. In the component-based modeling of angle connections, the five critical components of excessive deformation are identified. Constitutive relationships of angles, column panel zones, and contact between angles and column flanges, are derived by using only material and geometric properties and theoretical mechanics considerations. Those of slip and bolt hole ovalization are simplified by empirically-suggested mathematical representation and expert opinions. A mathematical model is then assembled as a macro-element by combining rigid bars and springs that represent the constitutive relationship of components. Lastly, the moment-rotation curves of the mathematical models are compared with those of experimental tests. In the case of a top-and-seat angle connection with double web angles, a pinched hysteretic response is predicted quite well by complete mechanical models, which take advantage of only material and geometric properties. On the other hand, to exhibit the highly pinched behavior of a top-and-seat angle connection without web angles, a mathematical model requires components of slip and bolt hole ovalization, which are more amenable to informational modeling. An alternative method is informational modeling, which constitutes a fundamental shift from mathematical equations to data that contain the required information about underlying mechanics. The information is extracted from observed data and stored in neural networks. Two different training data sets, analytically-generated and experimental data, are tested to examine the performance of informational models. Both informational models show acceptable agreement with the moment-rotation curves of the experiments. Adding a degradation parameter improves the informational models when modeling highly pinched hysteretic behavior. However, informational models cannot represent the contribution of individual components and therefore do not provide an insight into the underlying mechanics of components. In this study, a new hybrid modeling framework is proposed. In the hybrid framework, a conventional mathematical model is complemented by the informational methods. The basic premise of the proposed hybrid methodology is that not all features of system response are amenable to mathematical modeling, hence considering informational alternatives. This may be because (i) the underlying theory is not available or not sufficiently developed, or (ii) the existing theory is too complex and therefore not suitable for modeling within building frame analysis. The role of informational methods is to model aspects that the mathematical model leaves out. Autoprogressive algorithm and self-learning simulation extract the missing aspects from a system response. In a hybrid framework, experimental data is an integral part of modeling, rather than being used strictly for validation processes. The potential of the hybrid methodology is illustrated through modeling complex hysteretic behavior of beam-to-column connections. Mechanics-based components of deformation such as angles, flange-plates, and column panel zone, are idealized to a mathematical model by using a complete mechanical approach. Although the mathematical model represents envelope curves in terms of initial stiffness and yielding strength, it is not capable of capturing the pinching effects. Pinching is caused mainly by separation between angles and column flanges as well as slip between angles/flange-plates and beam flanges. These components of deformation are suitable for informational modeling. Finally, the moment-rotation curves of the hybrid models are validated with those of the experimental tests. The comparison shows that the hybrid models are capable of representing the highly pinched hysteretic behavior of beam-to-column connections. In addition, the developed hybrid model is successfully used to predict the behavior of a newly-designed connection.