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10 pages, 3159 KiB

Open AccessArticle

Laboratory Study on the Strength Behaviour of Two Laterally Loaded Adobe Walls

by Brad D. Weldon, Paola Bandini, Michael J. McGinnis, Eduardo Dávila and Diego I. García Vera

Infrastructures 2019, 4(1), 1; https://doi.org/10.3390/infrastructures4010001 - 21 Dec 2018

Cited by 2 | Viewed by 6035

Abstract

Adobe is a traditional construction technique found in historic and new construction throughout the world, often in earthquake-prone regions. Adobe structures are particularly susceptible to seismic forces due to their substantial mass and low tensile capacity. In addition, adobe is affected negatively by [...] Read more.

Adobe is a traditional construction technique found in historic and new construction throughout the world, often in earthquake-prone regions. Adobe structures are particularly susceptible to seismic forces due to their substantial mass and low tensile capacity. In addition, adobe is affected negatively by moisture that may penetrate from the ground or through the plaster. This paper describes the preliminary findings of an experimental program to investigate the effect of higher water content in the lower part of the wall on the wall strength behaviour under lateral loading. Lateral load tests were conducted on two quarter-scale adobe walls, one in air-dry condition (Wall 1) and another with greater water content in the lower part (Wall 2). The model walls demonstrated similar behaviour during loading in terms of deflections; however, the higher water content in the lower part had a significant effect on the wall strength. The in-plane (lateral) load capacity of Wall 2 was approximately 74% of the capacity of Wall 1. Full article

(This article belongs to the Special Issue Selected Papers from the REHABEND 2018 Congress)

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10 pages, 3324 KiB

Open AccessArticle

Experimental Analysis of the Strengthening of Reinforced Concrete Beams in Shear Using Steel Plates

by Marília M. Bez Batti, Bruno do Vale Silva, Ângela Costa Piccinini, Daiane dos Santos Godinho and Elaine Guglielmi Pavei Antunes

Infrastructures 2018, 3(4), 52; https://doi.org/10.3390/infrastructures3040052 - 16 Nov 2018

Cited by 6 | Viewed by 7384

Abstract

In some situations, it is necessary to strengthen or rehabilitate a structure in the short term, but before doing so, a critical analysis of the underlying causes is required to find the best technique to solve the problem. The structural strengthening is used [...] Read more.

In some situations, it is necessary to strengthen or rehabilitate a structure in the short term, but before doing so, a critical analysis of the underlying causes is required to find the best technique to solve the problem. The structural strengthening is used to increase an element’s ability to resist a stress when it no longer meets the original conditions or new necessities of use due to faults, deterioration, thermal variations, and lack of maintenance. The present article aims to evaluate the strengthening of reinforced concrete beams with 0.75 mm thick SAE 1020 steel plates bonded with epoxy-based structural adhesive. The steel plates were attached to the sheared area before and after the beams were taken to the breaking point load. According to the results, it was possible to conclude the effectiveness of the strengthening applied to healthy beams that had its bearing capacity increased up to 50%. The beam that was strengthened after the shear, with a fissure that was restored with epoxy-based structural adhesive, had its load bearing capacity increased by 49.2%. The beams with fissures that were filled with mortar had their bearing capacity decreased by 58.70% if compared with the reference beams, and thus they presented an unsatisfactory performance. Full article

(This article belongs to the Special Issue Selected Papers from the REHABEND 2018 Congress)

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10 pages, 25711 KiB

Open AccessArticle

Evaluation of the Bond-to-Concrete Properties of GFRP Rebars in Marine Environments

by Alvaro Ruiz Emparanza, Francisco De Caso Y Basalo, Raphael Kampmann and Itziar Adarraga Usabiaga

Infrastructures 2018, 3(4), 44; https://doi.org/10.3390/infrastructures3040044 - 8 Oct 2018

Cited by 19 | Viewed by 6438

Abstract

Increased traffic in combination with growing environmental impacts have led to the accelerated degradation of built infrastructure. In reinforced concrete structures, the corrosion of steel reinforcement is the predominant cause of deterioration. Thus, over the last years the use of glass fiber reinforced [...] Read more.

Increased traffic in combination with growing environmental impacts have led to the accelerated degradation of built infrastructure. In reinforced concrete structures, the corrosion of steel reinforcement is the predominant cause of deterioration. Thus, over the last years the use of glass fiber reinforced polymer (GFRP) composites as internal reinforcement bars (rebars) for concrete structures has been evaluated, and has been proved to be a viable alternative to traditional steel reinforcement mainly due to its tensile strength and non-corrosive nature. However, thus far, the GFRP rebar market is diverse and manufacturers around the world produce GFRP rebar types with different surface enhancements to improve the bond to concrete characteristics. In this study, the bond performance of three dissimilar GFRP rebar types (sand coated, helically grooved and with surface lugs) was evaluated over time in seawater environments, with a focus on the bond strength. Accordingly, specimens were exposed to seawater in circulating chambers at three different temperatures (23 °C, 40 °C and 60 °C) for multiple time periods (60 and 120 days). To evaluate the bond performance, pullout tests were conducted according to ASTM D7913. The results showed that the bond strength varied with the surface enhancement features. However, the bond strength did not vary significantly with exposure time and temperature for all three evaluated rebar types. Full article

(This article belongs to the Special Issue Selected Papers from the REHABEND 2018 Congress)

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20 pages, 10882 KiB

Open AccessArticle

Structural Behavior of the General Archive of the Nation (AGN) Building, Mexico

by Marcos M. Chávez, Fernando Peña, Claudia Cruz and Gustavo Monroy

Infrastructures 2018, 3(3), 39; https://doi.org/10.3390/infrastructures3030039 - 18 Sep 2018

Cited by 2 | Viewed by 5459

Abstract

This article presents a study on the structural behavior of the Government Building that is part of the old Lecumberri Palace and which currently houses the Mexican General Archive of the Nation. This building was inaugurated in 1900 and closed in 1976, after [...] Read more.

This article presents a study on the structural behavior of the Government Building that is part of the old Lecumberri Palace and which currently houses the Mexican General Archive of the Nation. This building was inaugurated in 1900 and closed in 1976, after serving as a prison for 76 years. It was reopened in 1982 after it had undergone several remodeling works. The construction is made of brick masonry with lime mortar. It is supported by a deposit of overly compressible high-plasticity clays. The main problems of this building are the appearance of cracks in both interior and exterior walls, and moisture in the ground floor, caused by differential settlements. The study entailed a geometric and a damage survey as well as ambient vibration tests in order to determine the dynamic properties of the construction. The data obtained was used for the making of a model that, using the finite element method, was analyzed under different load conditions. This study has focused on the overall response with the assumption of smeared crack damage. According to the results, the building’s safety was deemed as acceptable. It has the capability to withstand seismic actions as established by the Mexican Building Code due to the high density of its walls and the resulting stiffness, which infer that the fundamental vibration period of the building would be distant from the predominant vibration period of the soil. This highlights the idea that the building’s critical condition is constituted by the differential settlements, which cause damage in the construction. Full article

(This article belongs to the Special Issue Selected Papers from the REHABEND 2018 Congress)

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11 pages, 3081 KiB

Open AccessArticle

Experimental Study of the Mechanical Behaviour of Bricks from 19th and 20th Century Buildings in the Province of Zamora (Spain)

by Ana Belén Ramos Gavilán, María Ascensión Rodríguez Esteban, María Natividad Antón Iglesias, María Paz Sáez Perez, María Soledad Camino Olea and Julen Caballero Valdizán

Infrastructures 2018, 3(3), 38; https://doi.org/10.3390/infrastructures3030038 - 16 Sep 2018

Cited by 13 | Viewed by 5584

Abstract

Interventions in historic brick buildings require an exhaustive analysis of the current characteristics of bricks in order to establish the role performed by these elements in the buildings. This study presents the results of an experimental analysis of the compressive strength of brick [...] Read more.

Interventions in historic brick buildings require an exhaustive analysis of the current characteristics of bricks in order to establish the role performed by these elements in the buildings. This study presents the results of an experimental analysis of the compressive strength of brick specimens extracted from different buildings built in the 19th and 20th centuries in the province of Zamora (Spain). The study analyses specimens with very different characteristics to compare results from different masonry units and manufacturing processes. Specimens are classified into four groups according to their macroscopic and microscopic analyses. Compressive strength results are correlated to the above classification and to the results of density, absorption and open porosity of the samples. The compressive strength results present high variation between clay bricks (9.2–64.4 N/mm²) and between samples extracted from the same brick due to the heterogeneity of the material. Correlations between compressive strength and open porosity, absorption and dry density values are observed, with less dispersion in the case of high sintering level, up to 1000 °C. Finally, the compliance with the current Spanish Technical Building Code with respect to their compressive strength is checked. Full article

(This article belongs to the Special Issue Selected Papers from the REHABEND 2018 Congress)

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12 pages, 3419 KiB

Open AccessArticle

Durability and Compatibility of Lime-Based Mortars: The Effect of Aggregates

by Ana Rita Santos, Maria Do Rosário Veiga, Luís Matias, António Santos Silva and Jorge De Brito

Infrastructures 2018, 3(3), 34; https://doi.org/10.3390/infrastructures3030034 - 31 Aug 2018

Cited by 14 | Viewed by 5908

Abstract

In order to fully perform their functions and be durable, mortars for renders and plasters are requested to have a set of characteristics that can vary with the type of exposure to external environmental actions and the type of substrate. Generally, they need [...] Read more.

In order to fully perform their functions and be durable, mortars for renders and plasters are requested to have a set of characteristics that can vary with the type of exposure to external environmental actions and the type of substrate. Generally, they need moderate strength, high deformability, some water protection capability, good adhesion to the substrate and compatibility with the pre-existent materials. The presence of water and its movement inside the pore structure of the mortars are among the most significant causes of degradation. Moreover, several authors consider that the main factors for durability and good performance of lime-based mortars are mostly related with the good quality of the binder and the use of adequate aggregates. This paper intends to study the effect of ageing on the properties and durability of air lime mortars, using aggregates of different mineralogy. For this purpose, different mortars compositions are exposed to an accelerated weathering test under defined conditions. The obtained characteristics are discussed and compared with the results obtained with the same mortars tested in laboratory conditions. The effects of the aggregate type on the durability of mortars seem to be linked to their effects on the mortars porous structure. Full article

(This article belongs to the Special Issue Selected Papers from the REHABEND 2018 Congress)

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9 pages, 5987 KiB

Open AccessTechnical Note

Structural Safety Analysis of the Aqueducts “Coll De Foix” and “Capdevila” of the Canal of Aragon and Catalonia

by Albert De la Fuente, Vicente Alegre, Ana Blanco, Teresa Cavero and Roberto Quintilla

Infrastructures 2018, 3(4), 48; https://doi.org/10.3390/infrastructures3040048 - 5 Nov 2018

Cited by 1 | Viewed by 5392

Abstract

The Canal of Aragon and Catalonia (CAC) is 134 km long and irrigates 105,000 ha (131 irrigation user communities) and it is owned by the River Ebro’s Water Agency. The aqueducts are located between km 67 and 71 of the canal and were [...] Read more.

The Canal of Aragon and Catalonia (CAC) is 134 km long and irrigates 105,000 ha (131 irrigation user communities) and it is owned by the River Ebro’s Water Agency. The aqueducts are located between km 67 and 71 of the canal and were designed by the civil engineer Félix de los Ríos Martín in 1907. The cross-section of both aqueducts, Coll de Foix and Capdevila, was extended within the framework of the project by Fernando Hué Herrero in 1962 in order to reach design flows of 26.1 m³/s and 25.7 m³/s, respectively. The structural performance of the aqueducts has been satisfactory; nevertheless, the hydraulic capacity has reduced over the years. As a result, the irrigation user communities have expressed the need to extend the cross-section of the aqueducts to meet the irrigation demands. Given the age of the structure and the different design considerations at the time, it is paramount to verify the structural reliability of the aqueducts in the new load configuration. Therefore, the objective of this contribution is to present the structural safety analysis conducted and to describe the new extended cross-section for both aqueducts (maintaining the original structural typology). Full article

(This article belongs to the Special Issue Selected Papers from the REHABEND 2018 Congress)

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13 pages, 9569 KiB

Open AccessCase Report

Combination of Diagnostic Tools for the Proper Identification of Moisture Pathologies in Modern Residential Buildings

by Juan María Hidalgo-Betanzos, César Escudero-Revilla, Eider Iribar-Solaberrieta, Iván Flores-Abascal and José María Pedro Sala-Lizarraga

Infrastructures 2018, 3(3), 37; https://doi.org/10.3390/infrastructures3030037 - 14 Sep 2018

Cited by 1 | Viewed by 5430

Abstract

A study of moisture pathologies in a modern residential multifamily building is presented. The housing block was designed under the regulation NBE-CT of 1979 in northern Spain. After the appearance of some moisture problems in the façades, three complementary studies were conducted to [...] Read more.

A study of moisture pathologies in a modern residential multifamily building is presented. The housing block was designed under the regulation NBE-CT of 1979 in northern Spain. After the appearance of some moisture problems in the façades, three complementary studies were conducted to analyze the situation of the envelope and diagnose the best improvement possibilities. First, indoor conditions of temperature and humidity of the apartments with moisture pathologies were monitored. During 40 winter days, the occupancy, heating operation, and natural ventilation were analyzed. Second, the inner and outer surface temperatures of the studied façades were measured. Thermal insulation degree, thermal capacity, and thermal bridge effects were measured to assess the risk of interstitial condensation under the real conditions of use. Third, an infrared thermographic survey was carried out, which allowed the detection of irregularities and the assessment of moisture problems. The wrong interpretations, which would have been made if the complementary studies had not been done, are exposed. The key towards the accurate diagnosis was the combination of tools. Finally, some technical solutions based on ventilation or thermal insulation enhancement are proposed as different ways to reduce the high levels of relative humidity indoors and minimize the risk of condensation in the future. Full article

(This article belongs to the Special Issue Selected Papers from the REHABEND 2018 Congress)

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