Precast concrete wall panels

The seismic sequence which hit the Northern Italian territory in 2012 produced extensive damage to reinforced concrete (RC) precast buildings typically adopted as industrial facilities. The considered
damaged buildings are constituted by one-storey precast structures with RC columns connected to the ground by means of isolated socket foundations. The roof structural layout is composed of pre-stressed RC beams supporting pre-stressed RC floor elements, both designed as simply supported beams. The observed
damage pattern, already highlighted in previous earthquakes, is mainly related to insufficient connection strength and ductility or to the absence of mechanical devices, being the connections designed neglecting seismic loads or neglecting displacement and rotation compatibility between adjacent elements.
Following the vulnerabilities emerged in past seismic events, the paper investigates the seismic performance of industrial facilities typical of the Italian territory. The European building code seismic assessment methodologies are presented and discussed, as well as the retrofit interventions required to achieve an appropriate level of seismic capacity. The assessment procedure and retrofit solutions are applied to a selected case study.

In this research, the thermal properties of paraffin-impregnated burnt clay aggregate (PIA) concrete were studied. Paraffin was used as a phase change material (PCM) carrier and was incorporated into the burnt clay aggregates using heat and pressure. The compressive and flexural strengths of the concretes and the thermal insulation of the concrete panels were tested. The results of these tests revealed that the strengths and thermal insulation of the standard burnt clay aggregate concrete were improved with the use of PIA. The panels with PIA required more time to reach peak temperature and exhibited a larger drop in peak temperature relative to the control panel without PIA.

This paper presents experimental and numerical investigations on the behavior of axially-loaded concrete walls restrained on three sides (TW3S walls). Particular emphasis was given to the influences of varying the slenderness ratio, aspect ratio, concrete strength, and eccentricity on the ultimate axial strength of TW3S walls. Because of the overly conservative nature of the code design equations and the scarcity of other available models for estimating the ultimate axial strength of TW3S walls, a more encompassing design equation has been developed. Comparisons with the test data of the current and previous studies confirmed that the proposed equation is satisfactory and reliable.

Este artigo expõe as diretrizes para a criação de um processo de elaboração de projetos que utilizam painéis pré-fabricados de fachada, tendo como base o ambiente de Building Information Modeling (BIM). Os painéis pré-fabricados arquitetônicos de concreto (PPAC) foram utilizados como ponto de partida para a estruturação da proposta. A lógica de montagem justifica esta abordagem: assim como no sistema construtivo pré-fabricado, em que as peças são construídas fora do canteiro e chegam a este no momento da montagem, em BIM, os componentes da indústria da Arquitetura, Engenharia e Construção (AEC) são modelados independentemente e inseridos no momento oportuno no modelo. Foram realizados estudos teóricos sobre as características dos PPACs, seguidos de consulta a profissionais experientes do setor, para confirmação da seleção de dados e procedimentos necessários para o projeto. Em seguida, elaboraram-se fluxogramas de orientação para o processo de projeto. Uma simulação do procedimento proposto foi feita com o programa Revit 2013, para validação. A proposta procura auxiliar o projetista a definir os passos de projeto, bem como os dados para a modelagem dos elementos. Ao auxiliar projetistas a conceber projetos utilizando elementos pré-fabricados, procura-se facilitar e estimular seu uso mais frequente no país.

The modern-day popularity of tilt-up construction, shear walls and concrete cores in multi-storey buildings means that the construction of concrete walls with various boundary conditions and higher slenderness ratios, along with the presence of openings, has become common. The design of such elements under eccentric axial loads, however, could be outside the restrictions of current major design codes such as the Eurocode 2 (EC2-2004), the American Concrete Institute Code (ACI318-2014) and the Australian Concrete Standard (AS3600-2018). There have been many experimental and numerical studies on the behaviour of both one-way action walls and two-way action walls supported on four sides, with and without openings in the range of high slenderness ratios (up to 50). Efforts have also been made to develop design models capable of predicting the axial load capacity of such walls. However, research into the behaviour of two-way action walls supported on three sides (TW3S walls) is still relatively unexplored and further studies in this area are needed. Recent research has demonstrated that a rigid-plastic approach could be used to describe the behaviour of TW3S walls with and without openings. Although predictions obtained using the rigid-plastic approach showed reasonably good agreement with experimental test data, the scope of the analysis approach is considered limited. In this study, a validated finite element method, using the ABAQUS program, was employed to improve the rigid-plastic model, covering a broader spectrum of designs for axially-loaded TW3S walls. The reliability of the modified model was confirmed through comparisons with the available test data.

Precast concrete is a growing alternative to conventional cast-in-place concrete, especially for buildings in urban areas in Mexico. Precast concrete is well known for increasing construction speed and producing high-quality products. However, a common concern with precast concrete buildings in seismic areas is seismicresistant connections. This paper discusses testing of a typical practice in Mexico for connecting precast concrete members for moment-resisting frames using welded reinforcement. Results of cyclic lateral load testing of typical beam-column assemblies and the analysis of these connections using a nonlinear analytical model are discussed in this paper.

This 1992 paper reports on work in progress in 'Design for Energy Efficiency,' one of fifteen task areas of the U.S. Department of Energy sponsored Energy Efficient Industrialized Housing research program. In this task, design studies establish visions of energy efficient housing systems and technologies for the year 2030 from which shorter term research activities can be defined. One study for a 'Multifamily Concrete Panel House in a Hot-Arid Climate,' a primarily passive solar design, responds to trends anticipating demand for small, minimum cost multi-family houses in sun-belt suburbs, diversifying household composition, declining wood resources, advancing concrete technology, increasing site density, and competition for cooling energy. Task background and progress is presented with an emphasis on passive solar systems and goals.

The experimental study presented in this paper addresses the investigation of the precast Reinforced Concrete (RC) wall panels subjected to in-plane seismic loading conditions. The experimental elements were representative of four situations: (1) as-built blank solid wall, (2) with cutout door opening, (3) prior-to-damage strengthened by Externally Bonded Carbon Fiber Reinforced Polymer (CFRP EBR) composites and (4) post-damage strengthened by CFRP EBR.

Prezentul program experimental a fost conceput pentru a investiga comportarea pereților din panouri mari prefabricate de beton armat la care sunt executate goluri tăiate, supuse la acțiuni seismice în planul lor și în același timp, pentru a evalua eficiența soluției de consolidare folosind materiale compozite polimerice armate cu fibre. Tăierea golurilor în pereții structurali are ca efect modificarea locală a stării de eforturi și poate influența caracteristicile de comportare globală a structurii, în sensul de a reduce gradul de asigurare la acțiuni seismice. Intervențiile de tip tăiere gol apar predominant la parterul clădirilor, unde cerința de capacitate portantă este maximă, atât la sarcini gravitaționale cât și orizontale (seismice). În aceste condiții este necesar ca peretele structural afectat (cu gol tăiat) să fie consolidat, pentru a readuce parțial sau total la nivelul de capacitate portantă inițială.

No Brasil, tem-se observado o crescente uso de elementos pré-fabricados de concreto, nesse contexto, encontram-se os painéis de parede dupla pré-moldados que são um sistema construtivo formado por duas placas de concreto de pequena espessura mantidas unidas através de armadura treliçada. A armação estrutural necessária para todo o painel é construída dentro do componente pré-fabricado e após a instalação dos painéis, o espaço entre as placas pode ou não ser preenchido com concreto misturado e despejado no local da obra; neste sentido, o painel de parede dupla é um componente semi pré-fabricado. Esses painéis de fato combinam as maiores vantagens da pré-fabricação com as de uma parede fabricada em moldes concretados na obra. O presente trabalho apresenta uma investigação exploratória realizada através de revisão bibliográfica na qual será descrito e verificado as indicações de desempenho dos painéis de parede dupla pré-moldado conforme a recém lançada norma ABNT NBR 16475:2017, analisando criticamente os aspectos abordados e as lacunas deixadas pela a mesma; tendo com isto, o intuito de contribuir com a sistematização e difusão do tema na comunidade da construção civil brasileira.

Due to recent popularity of tilt-up construction and concrete cores in tall buildings, reinforced concrete (RC) walls are now considered just as important structural element as beams, slabs and columns. The Australian Concrete Standard, AS3600-09 for the simplified design of axially loaded walls allows for increased capacity due to side restraints compared with previous code of AS3600-01 and current American Concrete Institute Code, ACI318-14. Nevertheless, all of these codes do not significantly account for openings such as doors or windows. In view of the limitation, it is necessary to widen the scope of the methods and rectify the inadequacies which exist in these major national design codes. This paper presents shortcomings of the AS3600-09 and also reviews existing experimental tests by previous researches. It includes wall with various opening configurations and support conditions subjected to eccentric axial loading. Using the results obtained from previous experimental studies, a simple design method for various opening walls with support conditions has been derived. Comparisons are then made with the otheravailable empirical equations to highlight its accuracy, reliability and outstanding performance.