The papers presents the results of an experimental program and provides valuable information regarding the behaviour of structural masonry walls built up using ceramic blocks with hollows, which represents a very common system for low-rise residential buildings, up to 4 stories, depending on the seismic acceleration on site. A number of six masonry walls where tested in bear state being subjected to constant vertical loading and to cyclic in-plane horizontal loads. The main objective was to determine the shear capacity for unreinforced masonry walls and reinforced masonry walls. The experimental results were also useful to determine the contribution of the reinforcing of the masonry walls with concrete columns. The comparison between unreinforced masonry and reinforced masonry has a great importance due to the fact that the Romanian Seismic Standards have imposed the reinforcement in seismic areas for building with more than 1 storey. Further studies will be conducted on strengthening the masonry walls using FRP materials.
In the history of mankind, society was always heavily relying on the knowledge regarding their surroundings. Maps of already known areas were used in different areas of human activity, regardless if they were military applications or for plain orientation purposes. In the modern days of the 21st century, it is almost unimaginable for any corporate or private user to carry out their usual activity without precise knowledge of their (eventually larger than before) surroundings. One thing that changed in the past few years is that although people always used maps, the making of these were in the hand of certain specialists - the land surveyor engineers. Today, to a certain extent, any user can contribute to the expansion of existing maps (or even create new ones), thus leading to a vast dataset included in these maps. While this will theoretically further expand our knowledge regarding our surroundings, a natural question can come in everybody's mind: does the increasing quantity lead to unassailable quality as well? Can we enhance the reliability of existing maps and contribute to nearly error-free future maps?
G.M.T. Rădulescu, A.T.G. Rădulescu, M.V.G. Rădulescu and Sanda Naş
Structural Health Monitoring is an extremely complex and relatively expensive activity, and the current offer of tools, methods and technologies is varied, which can lead to a virtually high number of structural monitoring systems that can be customized for each case. In time, the monitoring of bridges became the engine for the development of SHM tools, methods and technologies, or manager monitoring systems. The case study, in continuous quasi-static condition, was performed on Incheon Grand Bridge South Korea. Tracking the behaviour of an objective under the influence of sunshine is performed by VCE Vienna Consulting Engineers ZT GmbH. This paper presents the effect of sunshine on a steel structural element, the first lamella front North line, by comparing data pairs that reflect the cause: steel temperature and the effect: the movement of a sensor mounted on the structural element. The analysis was performed using several software dedicated to mathematical modelling, trying to establish different mathematical models that can be tested and validated.
G.M.T. Rădulescu, A.T.G. Rădulescu, M.V.G. Rădulescu and Sanda Naş
We have seen in the previous paper that in the case of resistance elements made of steel, at least in this case study, the structure’s response to strains, in this case sunshine, is uncertain, may or may not be linear. The analysis continues for the four characteristic months of 2013, respectively the second month (February), the fifth (May), the eighth (August) and the event (November), covering the four seasons and approximately the entire range of temperatures to which the resistance elements of the bridge are subject to along a calendar year - case study Incheon Grand Bridge, Seoul, South Korea. The number of data pairs recorded, as we have noted, every 15 minutes, is initially 11,616, being difficult to process. Some software (e.g. Table Curve 2D) can work with a maximum of 3000 data pairs. In what follows we will examine the behaviour of a reinforced concrete element of the North Bridge Gap front line and we will build a mathematical model of its behaviour to sunshine, from the input data, one recording every hours, thus reducing the number of measurements to 2904. The aim is to obtain a mathematical model with a correlation coefficient above 0.9, which is also verified and validated. This model will allow us to calculate the expected position of the sensor mounted on the resistance element for a certain temperature, the degree of confidence of the result, the interval of residual values. Because the history of the evolution of temperatures for each moment analyzed is different it produces different results, but ones that fit the specified regressive mathematical model.
Full flat slabs can be enhanced by using spherical voids to replace the unemployed concrete from the core part of the slab. Therefore we get low self-weighted slabs that can reach a high range of spans, a low material consumption compared to classical solutions used so far. On the other hand, the upsides of these slabs pale against the insecurity in design stage about their punching and shear force behaviour. In this paper it is presented a parametric study about shear force behaviour of flat slabs with spherical voids used in standard condition service. The study was made using the Atena 3D finit element design software, starting form a numerical model gauged on experimental results on real models – scale 1:1. Based on these lab results, the model’s validation was made by overlapping the load – displacement experimental curves on the curves yielded from numerical analyses. The results indicate that under a longitudinal reinforcement rate of lower than 0.50%, flat slabs with spherical voids don’t fail to shear force and over this value the capable shear force decreases in comparison with solid slabs, as the reinforcement rate increases.
The article aims to present the results obtain from the scheduling and simulation of VLBI measurements in October 2010 for a period of three days for 24 hour continuous observations. To be sure that we will obtain good VLBI observation we have to do an optimization of the network. This can be done quite accurately by using the new modules that are part of the VLBI processing software’s, the modules scheduling and simulation. This can be considered the first step in preparation of the VLBI experiment. Very Long Baseline Interferometry (VLBI) it is a primary space-geodetic technique that it is able to determine precise coordinates on the Earth, by monitoring the variable of Earth orientation parameters (EOP) with high precision. Also Very Long Baseline Interferometry plays an important role for determination of celestial and terrestrial reference frame. It is also a technique that each year is more developed form a software and hardware point of view. To obtain the scans we used a set of eight different VLBI antennas and as a source we used different quasars. In the scheduling we used the source based strategy contrary to the station based approach and the radio sources where from updated catalogues according to the requirements of the VLBI2010 system, which means that we are able to obtain a best coverage of the celestial sphere. The results show that scheduling and simulation are very good tools in preparing real VLBI experiments.
The Precast Reinforced Concrete Wall Panel (PRCWP) presented in this paper is part of an experimental study regarding the seismic performance of precast reinforced concrete wall panels, strengthening strategies and investigation on the weakening induced by modifying the opening in these elements due to architectural demands, change of function of buildings or other reasons. The element presented is 1:1.2 scale typical Reinforced Concrete Wall Panel with a window opening used in Romania, in which the opening was changed to a door opening due to comfort considerations. The specimen was subjected to cyclic loading with the lateral loads being applied in displacement control of 0.1% drift ratio. This simulates the shear behaviour of the element. After testing the unstrengthen element we proceed to retrofit it using Carbon Fibre Strips anchored with Carbon Fibre Mash. The purpose of the paper is to present the strengthening strategy and restore the initial load bearing capacity of the element or even increase it. The experimental results of strengthen and unstrengthen specimens will be presented.