Editorial

The first issue of the fifth volume of the IBRACON Structures and Materials Journal is now released (Volume 5, Number 1, February 2012). The seven articles published in this issue cover relevant topics on concrete structures and materials. The first two address steel fiber reinforced concrete pipes: part 1 discusses technological analysis of the mechanical behavior and part 2 presents a numerical model to simulate the crushing test. Simplified damage models applied in the numerical analysis of reinforced concrete structures are presented in the third article. The fourth one reports studies on cement-base bearing pads for connections in precast concrete, focusing on the surface roughness. The influence of low temperature on the evolution of concrete strength is discussed in the fifth article. The sixth addresses reliability of buildings in service limit state for maximum horizontal displacements. The closing article presents a discussion on a variable limit for the instability parameter of wall-frame or core-frame bracing structures. We appreciate the interest and dedication of authors and reviewers, responsible for the consolidation of our journal. Thanks to them we are opening the fifth volume without interruptions or delays

Américo Campos Filho, José Luiz Antunes de Oliveira e Sousa, Luiz Carlos Pinto da Silva Filho and Romildo Dias Toledo Filho
Editors

Editorial

The IBRACON Structures and Materials Journal is now releasing this year's last issue (Volume 4, Number 5, December 2011). With these eight articles, our goal of publishing 40 items in 2011 has been reached. All the articles in this issue address relevant topics on concrete structures and materials. The first one addresses the possibility of intercalation of organic compounds within C-S-H nanostructure, aimed at the synthesis of nanocomposites with atypical properties. The second one discusses the structural behavior of reinforced concrete beams subjected to cyclic loadings through numerical and experimental analysis. The main objective is to quantify the increase in deflections of the beams subjected to repeated loading cycles. The third article compares different models to predict the compressive strength of reinforced masonry. The fourth presents a study on the use of solid waste as alternative aggregates for concrete manufacturing. The fifth discusses the shear strength of steel fiber-reinforced concrete beams. The sixth article reports an experimental investigation on the use of acoustic emissions to evaluate the modulus of elasticity of concrete. The development of artificial neural networks for interpreting ultrasonic pulse velocity of concrete is described in the seventh article. And finally, the last one presents a contribution to the obtainment of elastic modulus of concrete using micromechanics modeling. Thereby, the fourth volume of RIEM is closed. In four years a total of 105 articles and one technical note were published through 17 issues. With an ever increasing number of manuscript submissions, since June 2011 the periodicity of the releases began to change. Thenceforth, the issues that were previously quarterly became bimonthly, thus indicating a considerable growth in the importance of our journal in the concrete community. The dedication of our reviewers must also be noted, for they willingly donate their time to the voluntary task of maintaining the high standards of our Journal. In this issue, the last in volume 4, we acknowledge by name all the reviewers that collaborated with the Journal throughout the year of 2011.

Américo Campos Filho, José Luiz Antunes de Oliveira e Sousa, Luiz Carlos Pinto da Silva Filho and Romildo Dias Toledo Filho Editors

Editorial

A new issue of RIEM, the IBRACON Structures and Materials Journal (Volume 4, Number 4, October 2011), is now being released with eight articles and a technical note, addressing relevant themes on engineering applications of concrete. The first article presents a finite element model for simulating the three-dimensional behavior of reinforced concrete structures under monotonic loading. Nanoindentation techniques are exploited in the second article to analyze elastic modulus and hardness of cement paste. The third article introduces a proposal of a new and accelerated concrete prism test for evaluation of the potential reactivity of aggregates in the laboratory. A pull-out bond test for on-site quality control of structural concrete is described in the fourth article. The early-age behavior of high-strength concrete made with high initial strength cement and exposed to an environment with vibrations is addressed in the fifth article. The sixth article reports an experimental investigation conducted on 8 twoway reinforced concrete waffle flat slabs under centered load, focusing on the shear behavior of the ribs. An experimental study to evaluate the influence of the use of foundry sand residues on concrete properties is described in the seventh article. The eighth article presents a study of Brazilian concrete strength (non-) compliance and its effects on reliability of short columns. During these almost four years of RIEM, only the section articles has been active. However, other communication channels are open: technical notes and technical discussions on published articles. Technical notes are short communications of three or four pages on topics of general interest. In this issue, for the first time, a technical note is being published. In addition to eight articles, this issue brings a technical note on the implementation of a Levenberg-Marquardt algorithm to fit a softening curve to data from fracture tests on concrete specimens. We would like to thank the authors and reviewers for their involvement in maintaining the high level of RIEM. Their efforts are a fundamental contribution to our attempts towards the admission of our Journal in SciELO collection and other relevant scientific searching databases.

Américo Campos Filho, José Luiz Antunes de Oliveira e Sousa, Luiz Carlos Pinto da Silva Filho e Romildo Dias Toledo Filho - Editores

Editorial

We are pleased to release the third issue of 2011 of the IBRACON Structures and Materials Journal (Volume 4, Number 3, August 2011), with eight articles discussing relevant themes related to concrete structures and materials. The first article in this issue addresses the compressive strength of concrete block prisms, using a finite element package in a nonlinear analysis to compare numerical results
to experimental observations. The second article presents a performance evaluation of mechanical properties of self-compacting concrete prepared with different cements types submitted to steam curing.
Environmental variables in the concrete saturation degree modeling are discussed in the third article. The fourth article addresses effects of temperature changes on load transfer in plain concrete pavement joints. The fifth article focuses on the determination of rheological parameters of mortar and concrete by alternative techniques. An educational tool for design and detailing of reinforced concrete
columns is described in the sixth article. Stability of reinforced concrete buildings with flat slabs is discussed in the seventh article, focusing on the influence of frames with flat slab layers and inverted edge beams. The last article presents an efficiency evaluation of Branson’s equivalent inertia to consider physical nonlinearity of beams.
We would like to acknowledge authors and reviewers for the important contribution to this issue.
Thanks to your efforts we are maintaining the periodicity and punctuality, important for indexing our Journal.

Américo Campos Filho, José Luiz Antunes de Oliveira e Sousa, Luiz Carlos Pinto da Silva Filho and Romildo Dias Toledo Filho - Editors

Editorial

We are very glad to release the second issue of 2011 (Volume 4 Number 2) of the IBRACON Structures and Materials Journal (RIEM). Eight articles are being published addressing relevant and upto-date themes in the area of concrete structures and materials. The first article is related with the design optimization of concrete structures using a fully probabilistic approach. In their contribution the authors compare the fully probabilistic approach applied in agreement with Eurocode 2 and the partial reliability factor method of the same standard, showing that the former can satisfy the design requirements even when the latter does not. The second article presents a multi-phase model to account for concrete cracking based on a smeared crack approach, emphasizing its advantages in terms of reduced computational cost. In the third article, digital image processing was used to determine the aspect ratio, sphericity, flakiness ratio and shape factor of fine aggregates and how such geometrical aggregate characteristics affect mortar and concrete performance. In the fourth article the authors use MATLAB® programming for stress analysis in concrete gravity dams considering earthquake and silts. The fifth article presents a comparison of the use of pozolanic and non-pozolanic fine materials such as fly ash and fine sand in self-compacting concrete (SCC). The results presented indicated that the final cost of the fly ash-SCC was lower than that of the fine sand-SCC for similar strength levels. The objective of the sixth article is to perform thermal and structural analyzes of reinforced concrete beams and propose alternatives to the Eurocode recommendations in order to standardize them in view of the revision of the Brazilian standard ABNT NBR 15200. In the seventh article the authors compare experimental and theoretical results of a new strut-and-tie formulation for the design of precast column bases embedded in socket foundations with smooth interfaces. The last paper of this issue presents a probabilistic analysis of the strength data of the fiber reinforced concrete used in the construction of the Estaleiro Rio Grande Dry Dock. A correlation model between the concrete tensile and compressive strengths is also proposed by the authors. This issue is a result of the efforts of authors and reviewers from many national and international institutions. We would like to congratulate and thank all of you for your participation in the publication of this issue of RIEM.

Américo Campos Filho, José Luiz Antunes de Oliveira e Sousa, Luiz Carlos Pinto da Silva Filho
and Romildo Dias Toledo Filho - Editors

Editorial

We are pleased to release the first issue of a new volume (Volume 4 Number 1) of the IBRACON Structures and Materials Journal (RIEM). Professor Paulo Helene, who has been collaborating as Editor since RIEM´s first volume, is now being replaced by Prof. Romildo Dias Toledo Filho in the Editorial team. We thank Prof. Paulo Helene for his important contribution to RIEM. As a Former Editor, Prof. Paulo Helene will continue collaborating with our Journal as a member of the Editorial Board. We would also like to thank Prof. Romildo for accepting our invitation to join the Editorial team. In this issue seven articles are presented, dealing with interesting and up-to-date themes. The first article is related with the use of CFRP (carbon fiber reinforced polymer) as external reinforcement of beams. In the study the strengthening behavior of regular concrete beams is analyzed and compared with that of beams molded with cement mortar and short steel fibers. The second article presents a proposal of thermal performance evaluation of a one-storey housing typology, considering the use of cast-in-place monolithic panels of concrete, varying panel thickness and concrete density. The third paper reports an investigation about the flexural behavior of steel fibers reinforced self-compacting concrete beams. The fourth paper reports the consequences of erosions on concrete structures of urban stormwater channels, based on inspections in over 180 km of channels in the drainage system of Belo Horizonte city (Brazil). The fifth article presents the development of a mechanical model to reinforced concrete analysis based on the finite element method, taking into account the non-linear material behavior with shear strength mechanisms. The sixth article discusses the design, manufacture and constructions issues related to precast lattice-reinforced joist slabs in reinforced concrete structures. Motivated by reports on damage and collapse of existing RC building structures after recent earthquakes, the seventh article presents a comparative analysis, with special attention to the influence of bond-slip mechanisms on the cyclic behavior of structural elements reinforced with plain bars (poor bond properties) and deformed bars (good bond properties). Our journal, created in 2008 as a result of a successful combination of the former IBRACON Structural Journal and IBRACON Materials Journal, completed three years of publication without interruption. In the beginning, twenty articles were published per year. This number is increasing and our target is to publish forty articles per year in the near future. We know that this goal can only be reached with the interest of our members in submitting good quality papers and with the collaboration of our reviewers. We thank all of you for the efforts in making RIEM a relevant publication in the area of concrete structures and materials in the national and international scenario.

Américo Campos Filho, José Luiz Antunes de Oliveira e Sousa, Luiz Carlos Pinto da Silva Filho and Romildo Dias Toledo Filho , Editors

Editorial

We are now releasing the fourth and last issue of the third volume of RIEM, closing the third year of this Journal, which resulted from the combination of IBRACON Structural Journal and IBRACON Materials Journal. In this period RIEM experienced a significant development. Articles published in RIEM can be accessed through the search engine in the ACI site. We have reached the concept B2 in the QUALIS/CAPES system, which classifies articles published in RIEM in a significantly favorable level for Post-Graduate Programs. In this issue two articles deal with the application of concrete to floors: one addresses the influences of porosity and cure procedures on the flexural strength of paving concrete, and the other focuses on the addition of granite residue to tactile-floor alert strips for sight impaired people. Two articles evaluate the behavior of concrete when subjected to fire. Another article presents a panorama of international specifications and discusses the implementation of performance specifications in the industry of concrete. Numerical modeling of steel-concrete composite beams is discussed in the fifth article of this number, with emphasis on the structural behavior in the interface between steel and concrete. The last article deals with the application of the ultrasonic method to assess behavior of high performance concrete. In this issue we acknowledge the colleagues who acted as reviewers during the year 2010, a demanding and voluntary task of crucial importance to the development of our journal.

Américo Campos Filho, José Luiz Antunes de O. e Sousa, Luiz Carlos Pinto da Silva Filho e Paulo Helene , Editors

Editorial

The area of structures and constructions in plain, reinforced and pre-stressed concrete is developing very fast in Brazil in recent years, with a great technical development and strong investment in the upgrade and expansion of the country infrastructure.
At the same time it is comforting to observe that academic programs and associated research centers have also received generous funding and support from the public sector and, in some cases, established strong cooperation links with the industry. Today, there are 131 research groups related to concrete registered in the country, 22% of which are considered of excellence, with a demand to produce
and publish at an international level.

The subjects under study are the most varied, starting with materials science, conducted by researchers from Materials, Chemical and Civil Engineering, passing by Structural Engineering and reaching the systemic point of view from researches in Architecture and Urbanism. The IBRACON journal of scientific dissemination, classified in the system CAPES QUALIS as B2, was created and maintained with focus on these researchers. It is open to all visions and contributions aligned with improvement of the quality of life, economy of resources and energy, safety, robustness and sustainability of civil construction, in concrete and related materials.
In this issue seven articles of great interest are published: two of them reporting major studies regarding the interaction of the concrete structure with complementary systems. One examines the influence of foundation settlements, while the other deals with the influence of end conditions when composite cold-formed steel-concrete beams are connected to masonry in fire situations. In the field of structural rehabilitation there are two important contributions: one about the reinforcement of columns using self consolidating concrete, and the other focused on the comparison of compressive strength of mortars from laboratory tests with effective values observed in loco. An interesting and up-to-date article in the field of Materials treats the influence of lithium nitrate in the alkali-silica reaction. Finally, two articles are presented on the behavior of structures in use, one focusing on the monitoring of a 600m railway bridge and another on the seismic activity of the Northeastern Region of Brazil, recently affected by earthquakes. With this number, IBRACON believes to achieving one of the most important objectives of this vehicle, which is to provide researchers with qualified means for the dissemination of research and technical developments related to structures and materials for civil construction, enriching the Brazilian engineering and promoting knowledge exchange with researchers worldwide..

Américo Campos Filho (UFRGS, Porto Alegre, RS, Brazil), José Luiz Antunes de O. e Sousa (UNICAMP, Campinas, SP, Brazil), Luiz Carlos Pinto da Silva Filho (UFRGS, Porto Alegre, RS, Brazil) e Paulo Helene (São Paulo, SP, Brazil) , Editors

Editorial

We are now releasing the second issue of the third volume of our IBRACON Structures and Materials Journal (Vol. 3 Num. 2). In this issue an investigation on the ductility of reinforced concrete beams is reported in the first article. Material nonlinearity of concrete structures is the subject of the second article, in which design procedures based on lumped dissipation models are compared with simplified procedures recommended by the Brazilian code NBR 6118. In a third article, monitoring techniques are employed to compare design assumptions to actual behavior of reinforced concrete columns of tall buildings The fourth article presents mechanical properties of lightweight concrete, with a comparison to the corresponding properties of normal concretes. A teaching tool for studying skew bending
for general concrete cross-sections is described in the fifth article. The following article presents an attempt to classify environmental aggressiveness in the city of Salvador, BA. The issue closes with an article addressing the aerodynamic behavior of cable stayed bridges under simultaneous action of rain and wind.

The articles have been carefully reviewed by the Editorial Board and highly qualified reviewers from Brazil and from abroad. We deeply acknowledge their contribution, fundamental for the ever improving quality and regularity of our Journal. We would also like to thank all the authors that submitted articles for publication in our Journal, and renew the invitation to the whole concrete community, in Brazil and
abroad, to actively participate in the life of the IBRACON Structures and Materials Journal, as frequent readers or as contributors.

Américo Campos Filho, José Luiz Antunes de O. e Sousa and Paulo Roberto do Lago Helene, Editors

Editorial

We are now releasing the first issue of the third volume of our IBRACON Structures and Materials Journal (Vol. 3 Num. 1). This issue begins with an experimental study on Shrinkage modeling for recycled aggregate concretes. The second article brings the second part of “Design models for reinforced concrete strengthening in bending with Carbon Fiber Reinforced Polymers (CFRP)”, addressing
shear models. The third article describes the characterization of sugar cane bagasse ashes produced by controlled burning and ultrafine grinding. Computational modeling of steel fiber reinforced concrete beams subjected to shear is the subject of the fourth article. Aspects related to the evaluation of safety conditions of buildings during the structural repair of columns are discussed in the fifth
article of this issue.

We are now releasing the first issue of the third volume of our IBRACON Structures and Materials Journal (Vol. 3 Num. 1). This issue begins with an experimental study on Shrinkage modeling for recycled aggregate concretes. The second article brings the second part of “Design models for reinforced concrete strengthening in bending with Carbon Fiber Reinforced Polymers (CFRP)”, addressing
shear models. The third article describes the characterization of sugar cane bagasse ashes produced by controlled burning and ultrafine grinding. Computational modeling of steel fiber reinforced concrete beams subjected to shear is the subject of the fourth article. Aspects related to the evaluation of safety conditions of buildings during the structural repair of columns are discussed in the fifth
article of this issue.

Américo Campos Filho, José Luiz Antunes de O. e Sousa and Paulo Roberto do Lago Helene, Editors

Editorial

We are now releasing the fourth issue, closing the second volume of our IBRACON Structures and Materials Journal (Vol. 2 Num. 4). The first article of this issue addresses the behavior of fresh high performance concrete using a rheometer. The influence of the column cross section on the structural behavior of pile caps is discussed in a second article, based on experimental tests performed on two pile caps analyzed using the strut and tie model. Design models for reinforced concrete strengthening in bending with Carbon Fiber.

Reinforced Polymers (CFRP) are evaluated in a third article. Experimental tests performed by the authors are analyzed under ACI and fib guidelines, besides other models available in the literature. A fourth article shows results of experimental tests in reinforced concrete beam connections, in which the influences of concrete compressive strength and the amount of joint transversal reinforcement on
the relative rotations were investigated. The last article analyzes adequacy of a design method widely used to model waffle slabs in representing the slab behavior.

The articles have been carefully reviewed by the Editorial Board and highly qualified reviewers from Brazil and from abroad. In this issue we are pleased to nominate the IBRACON experts who participated as reviewers during 2009. We deeply acknowledge their contribution, fundamental for the ever improving quality and regularity of our Journal. We would also like to thank all the authors that submitted
articles for this second volume and renew the invitation to the whole concrete community, in Brazil and abroad, to actively participate in the life of the IBRACON Structures and Materials Journal.

Américo Campos Filho, José Luiz Antunes de O. e Sousa and Paulo Roberto do Lago Helene, Editors

Editorial

We are now releasing the second issue of the second volume of our IBRACON Structures and Materials Journal (Vol. 2 Num. 2). In this issue the use of non-destructive tests for the assessment of concrete properties is addressed, and correlation curves are proposed, based on specimens cast in several construction sites and laboratories in Rio de Janeiro. A second paper discusses criteria prescribed
by ABNT NBR 8800:2008 for design of composite slabs with respect to the prediction of ultimate strength, based on laboratory test results. The influence of steel fibers and mineral additions on cracking behavior of reinforced concrete tension members is evaluated in a third paper. Finite element simulation of reinforced concrete structures is focused in the fourth paper, comparing implementations
of the Multidirectional Smeared Crack Model and the Disturbed Stress Field Model. In the last paper, the grain size optimization of the raw meal for energy saving cement production is discussed, aiming at reduction of energy consumption.

The papers have been carefully reviewed by the Editorial Board and highly qualified reviewers from Brazil and from abroad. We acknowledge the reviewers’ contribution, fundamental for the publication of our Journal. We congratulate the authors of the papers presented in this issue. Again we invite all the concrete community in Brazil and abroad to participate in the activities of the IBRACON Structures and Materials Journal, as a frequent reader or as a contributor.

Américo Campos Filho, José Luiz Antunes de O. e Sousa and Paulo Roberto do Lago Helene, Editors

Editorial

We are now releasing the first issue of the second volume of our IBRACON Structures and Materials Journal (Vol. 2 Num. 1). In this issue a preliminary study to define the minimum shear reinforcement of flat slabs is presented in the first article. Properties of hardened SCC and similar conventional concrete in full-scale tests are compared in the second article. The third article brings a finite element based model to simulate the early age concrete behavior, aiming at the cracking risk assessment. Techniques to monitor the crack width and neutral axis position of steel fiber reinforced concrete beams are addressed in the fourth article. The fifth article presents correlations among mechanical properties of hollow blocks and those of the concrete used in its production.

The papers have been carefully reviewed by the Editorial Board and highly qualified reviewers from Brazil and from abroad. We acknowledge the reviewers’ contribution, fundamental for the publication of our Journal. We congratulate the authors of the papers presented in this issue. Again we invite all the concrete community in Brazil and abroad to participate in the activities of the IBRACON Structures and Materials Journal, as a frequent reader or as a contributor.

Américo Campos Filho, José Luiz Antunes de O. and Sousa e Paulo Roberto do Lago Helene, Editors

Editorial

We are now releasing the fourth issue of our IBRACON Structures and Materials Journal (Vol. 1 Num. 4), closing the first volume. Formulations, for estimating crack width in reinforced concrete pipes, available in the Brazilian Code for design of concrete structures (NBR 6118:2003), are discussed in the first article. A second article approaches the load capacity of pre-stressed concrete structures. The theory behind a tabular method for the fire design of concrete columns of the Brazilian Code for fire design of concrete
structures (NBR 15200:2004) is discussed in a third article, aiming at a contribution for a future edition of this code. The fourth article approaches the application of heat-activated films as a new generation of adhesives used for bonding fiber reinforced polymers and concrete. And the last article discusses the performance of bridges under DER-SP jurisdiction using the reliability index β and obtains truck weight limits in order to guarantee its structural integrity.
The papers have been carefully reviewed by the Editorial Board and highly qualified reviewers from Brazil and from abroad. In this issue we list the members who participate as reviewers for the current volume and for the papers in the reviewing process for the issues to come. We acknowledge their contribution, fundamental for the publication of our Journal. We congratulate the authors of the papers presented in this first volume. Again we invite all the concrete community in Brazil and abroad to participate in the activities of the IBRACON Structures and Materials Journal, as a frequent reader or as a contributor.

Américo Campos Filho, José Luiz Antunes de O. e Sousa and Paulo Roberto do Lago Helene, Editors

Editorial

We are now releasing the third issue of our IBRACON Structures and Materials Journal (Vol. 1 Num. 3). This issue brings a paper discussing safety of concrete-filled steel tubular columns according to Brazilian code NBR 8800:2008. Based on a reliability analysis for these columns, the authors suggest changes to the proposed text for updating this code. A second article addresses in situ evaluation of stress losses in unbonded tendons of post tensioned flat slabs of a sixteen-floor building in Belo Horizonte. The influence
of compression bars spacing on the behavior of contact and noncontact lap compression splices is evaluated in a third paper. An experimental analysis on the performance of reinforced concrete beams reinforced with GFRP bars is addressed in a fourth paper. The last paper presents a study of the optimum struts and ties angles for the models recommended by NBR 6118:2003, aiming at minimum steel consumption in reinforced concrete beams.
The papers have been carefully reviewed by the Editorial Board and highly qualified reviewers from Brazil and from abroad. We thank them for their support. We congratulate the authors of the papers presented in this issue. Again we invite all the concrete community in Brazil and abroad to participate in the activities of the IBRACON Structures and Materials Journal, as a frequent reader or as a contributor.

Américo Campos Filho, José Luiz Antunes de O. e Sousa and Paulo Roberto do Lago Helene, Editors

Editorial

We are pleased to release the second issue of the first volume of the IBRACON Structures and Materials Journal. This issue brings two articles on the recycling of residues: the first discusses the influence of surface treatment of tire rubber residues on mortars, and the other on the effect of the type of recycled aggregate from construction residues on the module of deformation of the concrete. Another article applies the strut-and-tie model to the study of deformations on the compressive diagonals in two-pile caps. A fourth article focuses on the compression in concrete masonry wallettes with cement mortar overlays. The last article analyzes the distribution of bending moments in RC buildings. All these topics are relevant and up-to-date, and certainly will raise the interest of our community. As usual, the papers have been reviewed by the Editorial Board, and by reviewers selected among IBRACON members, from Brazil and from abroad, with acknowledged competence in the specific areas. We thank the effort and dedication of the reviewers who have been collaborating for the consolidation of our Journal as a vehicle of recognized quality. We reiterate our invitation to the IBRACON members and other readers to submit their contributions to the IBRACON Structures and Materials Journal.

Américo Campos Filho, José Luiz Antunes de O. e Sousa and Paulo Roberto do Lago Helene, Editors