Use of Headed Reinforcement Bars in Contruction. A Theoretical Approach to Determine the Dimensions of Anchorage Plates and Experimental Tests on Knee Joints Subjected to a Closing Moment

In order to reduce costs and time while improving quality, durability and sustainability in structural concrete constructions, a widely used material nowadays, special care must be taken in some crucial phases of the project and execution, including the structure design and calculation, the dosage, dumping and curing of concrete: another important aspect is the proper design and execution of assembly plans and construction details. The framework, a name designating the whole reinforcement bars cage already assembled as shown in the drawings, can be made up of several components and implies higher or lower industrialization degree. The framework costs constitute about one third of the price per cubic meter placed in concrete works. The best solutions from all points of view are clearly those involving an easier processing to achieve the same goal, and consequently carrying a high degree of industrialization, meaning quality and safety in the work. This thesis aims to provide an indepth analysis of a relatively new type of anchoring by plate known as headed reinforcement bars, which can potentially replace standard or L-shaped hooks, improving the cleaning of construction details and enabling a faster, more flexible, and therefore a more economical assembly. A literature review on the topic and an overview of typical applications is provided, followed by some examples of specific applications in real projects. Since a strict theoretical formulation used to provide the design plate dimensions has not yet been put forward, an equation is proposed for the side-face blowout strength of the anchorage, based on the capacity of concrete to carry concentrated loads in cases in which no transverse reinforcement is provided. The correlation of the calculated ultimate load with experimental results available in the literature is given. Besides, the proposed formulation can be expanded to cases in which a certain development length is available: using a software for nonlinear finite element analysis oriented to the study of reinforced concrete, numerical tests on the bond-bearing interaction are performed. The thesis ends with a testing of eight corner joints subjected to a closing moment, held in the Structures Laboratory of the Polytechnic University of Madrid, aiming to check whether the design of such plates as stated is adequate for these elements and whether an element with plate-anchored reinforcement is equivalent to one with a traditional construction detail.

Characterization of rock joints by fractal analysis

From a physical perspective, a joint experiences fracturing processes that affect the rock at both microscopic and macroscopic levels. The result is a behaviour that follows a fractal structure. In the first place, for saw-tooth roughness profiles, the use of the triadic Koch curve appears to be adequate and by means of known correlations the JRC parameter is obtained from the angle measured on the basis of the height and length of the roughnesses. Therefore, JRC remains related to the geometric pattern that defines roughness by fractal analysis. In the second place, to characterise the geometry of irregularities with softened profiles, consequently, is proposed a characterisation of the fractal dimension of the joints with a circumference arc generator that is dependent on an average contact angle with regard to the mid-plane. The correlation between the JRC and the fractal dimension of the model is established with a defined statistical ratio.

Numerical evaluation of the vibration reduction index for structural joints

The present paper addresses the analysis of structural vibration transmission in the presence of structural joints. The problem is tackled from a numerical point of view, analyzing some scenarios by using finite element models. The numerical results obtained making use of this process are then compared with those evaluated using the EN 12354 standard vibration reduction index concept. It is shown that, even for the simplest cases, the behavior of a structural joint is complex and evidences the frequency dependence. Comparison with results obtained by empirical formulas reveals that those of the standards cannot accurately reproduce the expected behavior, and thus indicate that alternative complementary calculation procedures are required. A simple methodology to estimate the difference between numerical and standard predictions is here proposed allowing the calculation of an adaptation term that makes both approaches converge. This term was found to be solution-dependent, and thus should be evaluated for each structure.

A new approach for semi-automatic rock mass joints recognition from 3D point clouds

Rock mass characterization requires a deep geometric understanding of the discontinuity sets affecting rock exposures. Recent advances in Light Detection and Ranging (LiDAR) instrumentation currently allow quick and accurate 3D data acquisition, yielding on the development of new methodologies for the automatic characterization of rock mass discontinuities. This paper presents a methodology for the identification and analysis of flat surfaces outcropping in a rocky slope using the 3D data obtained with LiDAR. This method identifies and defines the algebraic equations of the different planes of the rock slope surface by applying an analysis based on a neighbouring points coplanarity test, finding principal orientations by Kernel Density Estimation and identifying clusters by the Density-Based Scan Algorithm with Noise. Different sources of information —synthetic and 3D scanned data— were employed, performing a complete sensitivity analysis of the parameters in order to identify the optimal value of the variables of the proposed method. In addition, raw source files and obtained results are freely provided in order to allow to a more straightforward method comparison aiming to a more reproducible research.

The pastrycook & confectioner's guide : for hotels, restaurants, and the trade in general adapted also for family use : including a large variety of modern recipes for bread, cakes, fancy biscuits, ice creams and water ices, jellies, pies, puddings and custards, joints, meat pies and dishes, poultry and game, ornamental sugar work & butter-work etc. : with useful hints and instructions /

"To build an ice-house": p. [57]-58.

Modern British permanent way. Treating of rails, chairs, fishbolts, fishplates, keys, sleepers, ballast, rail-joints, points and crossings, &c.

"Originally written as a series of articles for ʻThe Railway Newsʾ, in which they appeared at various periods between the years 1911 and 1914."--Pref.

Survey and correlation report on continuously reinforced pavements without joints, by W. H. Jacobs.

Mode of access: Internet.

Fatigue tests of plate joints and bolted lugs. ARO project. Final report, September 30, 1954.

Mode of access: Internet.

Studies of the fatigue behavior of butt-welded joints in HY-80 and HY-100 steels /

"AD no. 452191."

Liquid rocket disconnects, couplings, fittings, fixed joints, and seals /

Cover title.

A treatise on the theory and management of ulcers : with a dissertation on white swellings of the joints. To which is prefixed an essay on the chirurgical treatment of inflammation and its consequences /

Mode of access: Internet.

An account of a new method of treating diseases of the joints of the knee and elbow : : in a letter to Mr. Percival Pott /

Mode of access: Internet.

Methods of preparing horizontal construction joints in mass concrete /

Mode of access: Internet.

International and national standards on dimensional coordination modular coordination, tolerances and joints in building /

Item 247.

The carpenter and joiner's assistant. Containing practical rules for making all kinds of joints, and various methods of hingeing them together ... to which are added, examples of various roofs executed ... also extracts from M. Belidor, M. du Hamel, M. de Buffon, etc., on the strength of timber with practical observations.

Mode of access: Internet.