A numerical study into the evolution of loads on shores and slabs during construction of multistorey buildings. Comparison of partial striking with other techniques

This paper contains a summary and evaluation of an experimental research project carried out at the ICITECH laboratories, Valencia, Spain. The project consisted of the construction of a full-scale building that included a process of shoring, clearing and striking (SCS). The experimental model was used as the basis for the development of a FE model, including an evolving calculation, with the objective of simulating the construction process used, as well as studying the evolution of concrete properties during the test. The FE model was verified with the results obtained from the experimental model. Two further FE models were then developed from the original model and used to simulate the construction of the same building using two different construction processes: one involving shoring and striking (SS) and the other shoring, re-shoring and striking (SRS). Finally, the SCS was compared to the SS and SRS processes, respectively, and an analysis was made of the advantages and disadvantages of each one. The paper breaks new ground in that for the first time ever a comparative study is made of the three most frequently used shoring techniques. (C) 2010 Elsevier Ltd. All rights reserved.The authors would like express their gratitude to the Spanish Ministry for Science and Technology for funding the project (BIA2004-02085) and also to the Encofrados J. Alsina, Copasa, Lafarge and Ros Casares companies for their invaluable cooperation.Alvarado Vargas, YA.; Calderón García, PA.; Gasch, I.; Adam Martínez, JM. (2010). A numerical study into the evolution of loads on shores and slabs during construction of multistorey buildings. Comparison of partial striking with other techniques. Engineering Structures. 32(10):3093-3102. doi:10.1016/j.engstruct.2010.05.028S30933102321

Stage of construction: An essential consideration in designing reinforced concrete building structures

[EN] This paper analyzes the potential influence of the construction process on the serviceability stage of the structure of reinforced concrete (RC) buildings. For this, a number of cases of buildings erected by habitual construction processes were simulated by a finite elements model, including and excluding the construction process. The shoring¿clearing¿striking method was seen the least harmful to the long-term behavior, but even so maximum loads during construction exceeded the design loads. On the other hand, shoring¿reshoring¿striking procedure had construction loads similar to the design loads but worse long-term behavior. In view of the results obtained, it is of the utmost importance to consider the construction phase when designing building structures. Some practical recommendations are given to improve the consideration of the construction process in the design as well as to take into account the long-term behavior of structures due to load history during construction.Alvarado Vargas, YA.; Buitrago, M.; Gasch, I.; Prieto, CA.; Ardila, YA. (2018). Stage of construction: An essential consideration in designing reinforced concrete building structures. Structural Concrete. 19(6):1551-1559. https://doi.org/10.1002/suco.201700128S1551155919

Titin-Actin Interaction: PEVK-Actin-Based Viscosity in a Large Animal

Titin exhibits an interaction between its PEVK segment and the actin filament resulting in viscosity, a speed dependent resistive force, which significantly influences diastolic filling in mice. While diastolic disease is clinically pervasive, humans express a more compliant titin (N2BA:N2B ratio ~0.5–1.0) than mice (N2BA:N2B ratio ~0.2). To examine PEVK-actin based viscosity in compliant titin-tissues, we used pig cardiac tissue that expresses titin isoforms similar to that in humans. Stretch-hold experiments were performed at speeds from 0.1 to 10 lengths/s from slack sarcomere lengths (SL) to SL of 2.15 μm. Viscosity was calculated from the slope of stress-relaxation vs stretch speed. Recombinant PEVK was added to compete off native interactions and this found to reduce the slope by 35%, suggesting that PEVK-actin interactions are a strong contributor of viscosity. Frequency sweeps were performed at frequencies of 0.1–400 Hz and recombinant protein reduced viscous moduli by 40% at 2.15 μm and by 50% at 2.25 μm, suggesting a SL-dependent nature of viscosity that might prevent SL “overshoot” at long diastolic SLs. This study is the first to show that viscosity is present at physiologic speeds in the pig and supports the physiologic relevance of PEVK-actin interactions in humans in both health and disease

Cyclic behavior of ultra-high performance fiber reinforced concrete beam-column joint

[EN] Ultra-high performance fiber reinforced concrete (UHPFRC) is a unique class of fiber-reinforced concrete featuring ultra-high compressive strength and ductil e tensile strain hardening behavior, accompanied by multiple narrow cracking. Although many studies have confirmed its superior mechanical and damage tolerance properties under monotonic or blast loading, limited research has been carried out on the cyclic performance of UHPFRC structural members. This paper proposes the use of UHPFRC to improve the cyclic performance of structural elements. An experimental program was carried out on a large number of UHPFRC beam-column joint specimens under a cyclic lateral load. After the cyclic loading test, the following results were obtained: (a) hysterical performance, (b) maximum load, (c) maximum displacement, (d) the maximum energy dissipation (measured by hysteresis cycles), (e) stiffness degradation, (f) the cracking pattern, and (g) the cracking area. The analysis showed that UHPFRC specimens have at least 157% higher energy dissipation than nonfiber conventional reinforced concrete (RC). The initial stiffness of UHPFRC specimens without fibers (NF) was at least 23% higher than the RC specimen. For UHPFRC with fiber, initial stiffness was at least 45% higher than RC specimen.This work was supported by Cementos Argos, Colciencias and the Pontificia Universidad Javeriana, Bogotá (Colombia).Sarmiento, PA.; Torres Górriz, B.; Ruiz, DM.; Alvarado Vargas, YA.; Gasch, I.; Machuca, AF. (2019). Cyclic behavior of ultra-high performance fiber reinforced concrete beam-column joint. Structural Concrete. 20(1):348-360. https://doi.org/10.1002/suco.201800025S34836020

Improving construction processes of concrete building structures using load limiters on shores

This paper analyses the redistribution of maximum loads using a system of load limiters on shores in which the limiters yield at a given load and thus reduce the maximum load absorbed by the shores. For this analysis a finite element modelling (FEM) of an experimental building was developed in which load limiters had been fitted to the shores to restrict their maximum load to a given value. This was designed to: (a) optimise slab construction costs by using shores of lower load-bearing capacities, (b) improve safety during the construction of consecutive concrete slab floors by reducing maximum loads and redistributing loads amongst the shores; and (c) increase structural efficiency by more efficient use of the materials employed due to load redistribution. It has been estimated that using load limiters in this way can reduce total shoring costs in a building project by between 30% and 40%.The authors would like to express their gratitude to the Universitat Politecnica de Valencia for funding this research project (PAID-06-11) and also to the Encofrados J. Alsina Company for their invaluable cooperation.Buitrago Moreno, M.; Alvarado Vargas, YA.; Adam Martínez, JM.; Calderón García, PA.; Gasch, I.; Moragues, JJ. (2015). Improving construction processes of concrete building structures using load limiters on shores. Engineering Structures. 100:104-115. doi:10.1016/j.engstruct.2015.06.007S10411510

Estudio técnico económico de alternativas del proceso de cimbrado y descimbrado en la construcción de un edificio de forjados de losa maciza de hormigón armado

[EN] The aim of this paper is to define alternative construction processes for a building with reinforced concrete slab floors, thereby estimating which ones are most beneficial in terms of their execution time and cost. Three alternatives were proposed to solve the deadlines of the construction process: Shoring and Striking; Shoring, Clearing and Striking; and Shoring, Reshoring and Striking, considering 2, 3 and 4 consecutive shored floors. In order to evaluate what processes are valid, first it is necessary to calculate the loads during the construction process using the New Simplified Procedure and subsequently check whether or not the striking condition is fulfilled in each of the construction operations. Regarding the studied building, the feasible construction processes were: Shoring, Clearing and Striking with 3 and 4 consecutive shored floors[ES] El objetivo del presente trabajo es definir diferentes alternativas de procesos constructivos, estimando cuáles resultan ser las más beneficiosas respecto a su plazo de ejecución y su coste, para un edificio de forjados de losa maciza de hormigón armado. Para resolver los plazos de ejecución se plantearon tres alternativas del proceso constructivo: Cimbrado y Descimbrado; Cimbrado, Clareado y Descimbrado; y Cimbrado, Recimbrado y Descimbrado, considerado 2, 3 y 4 plantas consecutivas apuntaladas. Para evaluar qué procesos son válidos, primero se calculan las cargas que se presentan durante el proceso constructivo mediante el Nuevo Procedimiento Simplificado y posteriormente se comprueba si se cumple o no, en cada una de las operaciones constructivas, la condición de descimbrado. Para el edificio objeto de estudio se han obtenido como procesos viables económica y técnicamente los procesos constructivos de Cimbrado, Clareado y Descimbrado con 3 y 4 plantas cimbradas.Alvarado Vargas, YA.; Gasch, I.; Calderón García, PA.; Torres Górriz, B. (2016). Estudio técnico económico de alternativas del proceso de cimbrado y descimbrado en la construcción de un edificio de forjados de losa maciza de hormigón armado. Revista Ingeniería de Construcción. 31(2):117-126. doi:10.4067/S0718-50732016000200005S11712631

Challenges and Rewards in Medicinal Chemistry Targeting Cardiovascular and Metabolic Diseases

Medicinal chemistry has been transformed by major technological and conceptual innovations over the last three decades: structural biology and bioinformatics, structure and property based molecular design, the concepts of multidimensional optimization (MDO), in silico and experimental high-throughput molecular property analysis. The novel technologies advanced gradually and in synergy with biology and Roche has been at the forefront. Applications in drug discovery programs towards new medicines in cardiovascular and metabolic diseases are highlighted to show impact and advancement: the early discovery of endothelin antagonists for endothelial dysfunction (Bosentan), 11-beta hydroxysteroid dehydrogenase (11?-HSD1) inhibitors for dysregulated cellular glucocorticoid tonus (type 2 diabetes and metabolic syndrome) and non-covalent hormone sensitive lipase (HSL) inhibitors to study the scope of direct inhibition of lipolysis in the conceptual frame of lipotoxicity and type 2 diabetes

Estudio técnico económico de los procesos de cimbrado y descimbrado en edificaciones. Estudio de caso en Bogotá, Colombia

[EN] This paper evaluates the economic benefits of shorter construction times that can be attained by applying the New Simplified Procedure (NSP) in multi-storey buildings. The reference building was a multi-storey residential reinforced concrete framework structure with one-way slabs located in Bogotá, Colombia. The study was divided into different phases including the characterization of the components, a study of the different methods to determine load transmissions between slabs and shores, and a review of the cost of renting shoring and formwork materials and labor costs for the building under study. After applying the procedure, an economic assessment was carried out on the execution times obtained in each of the operations studied. The analysis of the construction process of the building structure using the NSP showed that considerable savings can be achieved in construction times without any risk for the integrity of the structure.[ES] El presente artículo evalúa el beneficio económico de la aplicación del Nuevo Procedimiento Simplificado (NPS), reflejado en los plazos de construcción en edificaciones de entrepisos sucesivos. El edificio de referencia corresponde a un edificio residencial resuelto con pórticos y entrepisos en una dirección, de concreto reforzado ubicado en la ciudad de Bogotá. Las fases desarrolladas en cumplimiento del objetivo planteado, constaron de una caracterización de los componentes, el estudio de distintas alternativas para determinar la transmisión de cargas entre entrepisos y puntales, y una revisión de los precios de alquiler de equipo auxiliar y personal del edificio de referencia. Aplicando dicho procedimiento se realizó una evaluación económica de los plazos obtenidos en cada una de las operaciones estudiadas. Se destaca que el análisis del proceso constructivo de la estructura de la edificación empleando el NPS permite lograr ahorros considerables en la ejecución de la edificación sin poner en riesgo la integridad de la estructura.Alvarado Vargas, YA.; Pérez Gómez, MI.; Castellanos Reyes, JA.; Gasch, I. (2016). Technical and economic study of striking and clearing operations in buildings under construction. Case study in Bogotá, Colombia. DYNA. 83(199):102-107. doi:10.15446/dyna.v83n199.56086S1021078319

Performance of pervious concrete containing combined recycled aggregates

This study evaluates the influence of incorporating two different types of recycled aggregates (RA) from construction and demolition waste (CDW), brick ceramic aggregate (RA1) and crushed concrete aggregate (RA2), from the city of Bogotá, on the performance of pervious concrete under compression and flexural strength. The substitution of RA in the production of pervious concrete is outlined, taking into account five substitution levels. For the pervious concrete mixes, aggregates of sizes retained in a sieve of 1/2” and 3/8” were used. The pervious concrete mixes were submitted, 28 days later, to density tests, void content, compression and flexural strength and permeability. Such pervious concrete with RA reaches compression and flexural strength of up to 5,79 MPa and 2,14 MPa, respectively, which are within the allowed range by the ACI, reaching a permeability of 24,79 mm/s, value that is superior to the common characteristics of pervious concreteEn este estudio se evaluó la influencia de la incorporación de dos diferentes tipos de agregados reciclados (RA) provenientes de residuos de la construcción y demolición (CDW), agregado de ladrillo cerámico (RA1) y agregado de hormigón triturado (RA2), de la ciudad de Bogotá, en el desempeño a compresión y flexión de concreto permeable. Para esto se planteó la sustitución de RA en la producción de concreto permeable considerando cinco niveles de sustitución. Para la fabricación de este concreto permeable se utilizaron agregados de tamaños retenidos en el tamiz de 1/2” y 3/8”. Las mezclas de concreto permeable fabricadas se sometieron a ensayos de densidad, contenido de vacíos, resistencia a la compresión, módulo de rotura y permeabilidad, a los 28 días. Dicho concreto permeable con RA alcanza resistencias a compresión y módulo de rotura de hasta 5,79 MPa y 2,14 MPa, respectivamente, que se encuentran dentro del rango permitido por la ACI, alcanzando una permeabilidad de 24,79 mm/s, valor que es superior a las características comunes de un concreto permeable