An analytical approach for pull-out behavior of TRM-strengthened rammed earth elements

Rammed earth constructions, beyond being largely spread in the built heritage, are known for their high seismic vulnerability, which results from high self-weight, lack of box behavior and low mechanical properties of the material. Hence, to mitigate this seismic vulnerability, a compatible textile reinforced mortar (TRM) is here proposed as a strengthening solution, because of its reduced mass and high ductility. The few research about the structural behavior of TRM-strengthened rammed earth elements addresses the global behavior, overlooking the local behavior of the system. An analytical approach to infer the bond stress-slip relationship following the direct boundary problem is proposed. Based on a previous series of pull-out tests, an adhesion-friction constitutive law is portrayed considering also a damage model that considers the degradation of the reinforcing fibers due to friction.This work was partly financed by FEDER funds through the Operational Programme Competitiveness Factors (COMPETE 2020) and by national funds through the Foundation for Science and Technology (FCT) within the scope of project SafEarth - PTDC/ECM-EST/2777/2014 (POCI-01-0145-FEDER-016737). The support from grant SFRH/BD/131006/2017 is also acknowledged

Effectiveness of a TRM solution for rammed earth under in-plane cyclic loads

To evaluate the effectiveness of a TRM-strengthening solution for rammed earth walls subjected to in-plane cyclic loads, an experimental program was conducted on a strengthened mock-up previously damaged. The experimental results are discussed in comparison with the previous unstrengthened model in terms of cracking pattern, damage identification, displacements, base shear coefficient, stiffness degradation, and energy dissipation; in addition, simplified equivalent linear and bi-linear systems are inferred to assess the performance. The outcomes highlighted the effectiveness of the TRM solution in improving the in-plane shear capacity, the ductility and the dissipated energy of the mock-up.This work was partly financed by FEDER funds through the Operational Programme Competitiveness Factors (COMPETE 2020) and by national funds through the Foundation for Science and Technology (FCT) within the scope of project SafEarth - PTDC/ECM-EST/2777/2014 (POCI-01-0145-FEDER-016737). The support from grants SFRH/BD/131006/2017 and SFRH/BPD/97082/2013 is also acknowledged. Acknowledgments are addressed to the Laboratory of Structures (LEST) of the University of Minho and to João Bernardino, Lda. and TERRACRUA - Construções Ecológicas Unipessoal, Lda for building the rammed earth model

Performance of rammed earth subjected to in-plane cyclic displacement

Rammed earth structures are worldwide spread, both as architectural heritage and new constructions. Yet, rammed earth buildings present, in general, high seismic vulnerability. Despite the several studies conducted on the mechanical characterisation of rammed earth and on the numerical modelling of structural elements built with this material, further in-plane cyclic tests on rammed earth sub-assemblies are required to characterise their hysteretic behaviour. In this framework, an experimental program was conducted where cyclic in-plane tests were performed on a large-scale rammed earth wall. The geometry of the wall was defined to represent a sub-assembly commonly found in rammed earth dwellings from Alentejo (Southern Portugal). The wall was subjected to cyclic shear displacements with increasing amplitude, imposed in both positive and negative directions. To detect the dynamic properties of the wall and to assess the development of the structural damage, dynamic identification tests were conducted along the experimental programme. The results are analysed in terms of crack pattern, dynamic properties, displacement capacity, base shear performance and stiffness degradation. Further discussion is led on the dissipated energy, while a bi-linear and linear equivalent systems are proposed as simplified modelling approach. In conclusion, degradation of structural capacity was observed due to cyclic loads, while adequate energy dissipation and base shear coefficient were obtained.This work was partly financed by FEDER funds through the Operational Programme Competitiveness Factors (COMPETE 2020) and by national funds through the Foundation for Science and Technology (FCT) within the scope of project SafEarth-PTDC/ECM-EST/2777/2014 (POCI-01-0145-FEDER-016737). The support from grants SFRH/BD/131006/2017 and SFRH/BPD/97082/2013 is also acknowledged. Acknowledgments are addressed to the Laboratory of Structures (LEST) of the University of Minho, Joao Bernardino, Lda, and TERRACRUA-Construcoes Ecologicas Unipessoal, Lda for building the rammed earth model

Seismic behaviour and strengthening of rammed earth constructions

The widespread use of earthen buildings can be accredited to the local availability of the raw material, sustainability of the building process, and low cost. Earthen structures suffer from high seismic vulnerability, resulting from the low strength of the material, high mass, and lack of engineering approaches in design and building. Despite the extensive use of rammed earth structures, the structural behaviour of such buildings is still not well known, particularly concerning the in-plane and out-of-plane response under cyclic loads. Moreover, proper strengthening solutions are still required to reduce seismic vulnerability. In this context, an experimental program was conducted on the in-plane and out-of-plane cyclic performance of rammed earth structural sub-assemblies. The prototypes, after being damaged, were strengthened by employing a TRM-based solution and subjected to further testing. The experimental results are reported and discussed in terms of cracking pattern and peak base shear coefficient. Finally, the effectiveness of the proposed strengthening solution was evaluated against the performance of the unstrengthened mockups. The outcomes highlighted the effectiveness of the TRM solution in improving the ductility and the in-plane shear capacity of the mockups.This work was partly financed by FEDER funds through the Operational Programme Competitiveness Factors (COMPETE 2020) and by national funds through the Foundation for Science and Technology (FCT) within the scope of project SafEarth—PTDC/ECM-EST/2777/2014 (POCI-01–0145-FEDER-016737). The support from grants SFRH/BD/131006/2017 and SFRH/BPD/97082/2013 is also acknowledged. Acknowledgments are addressed to the Laboratory of Structures (LEST) of the University of Minho, João Bernardino Lda and TERRACRUA Lda for building the rammed earth model

Reliability and resilience of wastewater networks

The wastewater network is a critical infrastructure in a community and damages or disruption due to a hazard event implicate consequences in the economic security, public health and wellness of the community. Therefore, using an index to evaluate the vulnerability and the functionality of the system is essential for designers and utility managers for the design, operation and protection of wastewater network. In this paper, a functionality index for the wastewater network has been proposed that is the product of three different indices: (i) the number of users still connected to the system, (ii) the quality of sewer discharge into the water body after the treatment, in term of two pollutants, biochemical oxygen demand and total suspended solids, and (iii) the presence of leaks into the network. Seaside, a small city in Oregon, in the West cost of USA has been selected as case of study using an earthquake scenario and a restoration plan. The results show the critical elements of the networks that under the observed operating conditions would not be able to present reliable performances. Using the proposed indices in a decision support tool for governmental agencies could give guidelines for the restoration of elements that have more weight in the functionality of the system

Microwave-Assisted Treatment of Waste Wood Biomass with Deep Eutectic Solvents

Abstract. The increasing depletion of fossil feeds and the environmental concerns linked to the use of traditional energy sources have stimulated both academic and industrial worlds in exploiting new sustainable and renewable suppliers of raw materials [1]. In this framework, lignocellulosic biomass can play an important role, acting as the starting material of a biorefinery leading to biofuels, chemicals, and other value-added products, commonly obtained from petroleum. Recently, numerous protocols for processing lignocellulosic biomass of selected plants have been reported. However, developing an environment-friendly method is still a big goal. This challenge becomes more interesting if lignocellulosic biomass coming from wood wastes could be efficiently treated. Deep eutectic solvents (DESs) are new sustainable and cheap reaction media, combining the features of ionic liquids and organic solvents. They are made by association of hydrogen-bond donors and hydrogen-bond acceptors, and they can promote the hydrolysis of lignocellulosic bonds [2]. Herein, we report on the microwave-assisted treatment of waste wood flours with DESs formed by choline chloride and oxalic acid to get a cellulosic residue separated from lignin degradation products, identified by NMR spectroscopy. The insoluble deposit was characterized by SEM, TGA, DSC, FTIR-ATR and 13C CP/MAS NMR techniques and could be available for further uses such as nanocellulose production. [1] Haldar D., Purkait M.K. Chemosphere 2021, 128523. [2] Liu S., Zhang Q., Gou S., Zhang L., Wang Z. Carbohydr. Polym. 2021, 251, 11701

Coastal hydrogeological system of Mar Piccolo (Taranto, Italy)

The Mar Piccolo basin is an internal sea basin located along the Ionian coast (Southern Italy), and it is surrounded primarily by fractured carbonate karstic environment. Because of the karstic features, the main continental water inflow is from groundwater discharge. The Mar Piccolo basin represents a peculiar and sensitive environment and a social emergency because of sea water and sediments pollution. This pollution appears to be caused by the overlapping effects of dangerous anthropogenic activities, including heavy industries and commercial and navy dockyards. The paper aims to define the contribution of subaerial and submarine coastal springs to the hydrological dynamic equilibrium of this internal sea basin. A general approach was defined, including a hydrogeological basin border assessment to detect inflowing springs, detailed geological and hydrogeological conceptualisation, in situ submarine and subaerial spring measurements, and flow numerical modelling. Multiple sources of data were obtained to define a relevant geodatabase, and it contained information on approximately 2,000 wells, located in the study area (1,600 km2). The conceptualisation of the hydrogeological basin, which is 978 km2 wide, was supported by a 3D geological model that interpolated 716 stratigraphic logs. The variability in hydraulic conductivity was determined using hundreds of pumping tests. Five surveys were performed to acquire hydro-geochemical data and spring flow-yield measurements; the isotope groundwater age was assessed and used for model validation. The mean annual volume exchanged by the hydrogeological basin was assessed equal to 106.93 106 m3. The numerical modelling permitted an assessment of the mean monthly yield of each spring outflow (surveyed or not), travel time, and main path flow

Evaluating the seismic behaviour of rammed earth buildings from Portugal: From simple tools to advanced approaches

Despite the use of rammed earth became marginal in the second half of the past century, Portugal still holds an important built heritage. Recently, a growing use of rammed earth has been observed in modern constructions, but it is putting aside the roots of traditional rammed earth construction. The seismic behaviour of rammed earth buildings is still insufficiently comprehended, constituting a matter of great concern, since most of the traditional dwellings are built on regions with important seismic hazard. Moreover, the complex architecture of modern rammed earth buildings is expected to make their seismic behaviour even more fragile. This paper intends to provide a better comprehension on the seismic behaviour of rammed earth constructions from Portugal. For this purpose, twenty traditional dwellings were evaluated on the basis of a simplified approach, while a modern construction was investigated by means of destructive and non-destructive testing approaches. The main findings of these approaches are discussed in detail, but it can be highlighted that the architectural features of traditional rammed earth buildings benefit their seismic behaviour, while the complex architecture of modern rammed earth buildings demands using advanced engineering tools for their seismic assessment.This work was partly financed by FEDER funds through the Competitivity Factors Operational Programme - COMPETE and by national funds through FCT Foundation for Science and Technology within the scope of projects POCI-01-0145-FEDER-007633 and POCI-01-0145-FEDER-016737 (PTDC/ECM-EST/2777/2014). The support from grant SFRH/BPD/97082/2013 is also acknowledged. The authors wish also to express gratitude to Eng. Sergio Morgado and Mr. Francisco Seixas for providing access to the house of Forjales and conditions to perform the destructive and non-destructive tests.info:eu-repo/semantics/publishedVersio