Paddy Engineering Consultant

Poor construction methods and workmanship is responsible for the failure of buildings and structure. The poor construction methods and workmanship is caused due to negligence and inadequate quality control at construction site. The effects of some of the poor construction methods are discussed below: Poor construction methods and workmanship (a) Incorrect placement of steel Incorrect placement of steel can result in insufficient cover, leading to corrosion of the reinforcement. If the bars are placed grossly out of position or in the wrong position, collapse can occur when the element is fully loaded. (b) Inadequate cover to reinforcement Inadequate cover to reinforcement permits ingress of moisture, gases and other substances and leads to corrosion of the reinforcement and cracking and spalling of the concrete. (c) Incorrectly made construction joints The main faults in construction joints are lack of preparation and poor compaction. The old concrete should be washed...

Cracking caused by plastic shrinkage in concrete occurs most commonly on the exposed surfaces of freshly placed floors and slabs or other elements with large surface areas when they are subjected to a very rapid loss of moisture caused by low humidity and wind or high temperature or both. Plastic shrinkage usually occurs prior to final finishing, before curing starts. When moisture evaporates from the surface of freshly placed concrete faster than it is placed by curing water, the surface concrete shrinks. Due to the restraint provided by the concrete on the drying surface layer, tensile stresses develop in the weak, stiffening plastic concrete, resulting in shallow cracks that are usually not short and run in all directions. In most cases, these cracks are wide at the surface. They range from a few millimeters to many meters in length and are spaced from a few centimeters to as much as 3 m apart. Preventing Plastic Shrinkage Cracks in Concrete Plastic shrinkage cracks may exte...

Factors that affects the concrete mix design strengths are: Variables in Mix Design A. Water/cement ratio B. Cement content C. Relative proportion of fine & coarse aggregates D. Use of admixtures A. Water/cement ratio Water to cement ratio (W/C ratio) is the single most important factor governing the strength and durability of concrete. Strength of concrete depends upon W/C ratio rather than the cement content. Abram’s law states that higher the water/cement ratio, lower is the strength of concrete. As a thumb rule every 1% increase in quantity of water added, reduces the strength of concrete by 5%. A water/cement ratio of only 0.38 is required for complete hydration of cement. (Although this is the theoretical limit, water cement ratio lower than 0.38 will also increase the strength, since all the cement that is added, does not hydrate) Water added for workability over and above this water/cement ratio of 0.38, evaporates leaving cavities in the concrete. These caviti...

Construction Materials management can be defined as "the function responsible for the coordination of planning, sourcing, purchasing, moving, storing and controlling materials in an optimum manner so as a pre-decided service can be provided at a minimum cost". By another definition, "materials management can be said to be that process of management which coordinates, supervises and executes the tasks associated with the flow of materials to, through, and out of an organization in an integrated fashion". Lee and Dobler define materials management as, "a confederacy of traditional materials activities bound by common idea – the idea of an integrated management approach to planning, acquisition, conversion, flow and distribution of production materials from the raw material state to the finished product state." From the above definitions, it is clear that the scope of materials management is vast. It has, directly or indirectly, impact on the activities ...

Repair of small, medium and large cracks in concrete and repair of crushed concrete is required to enhance the strength and durability of damaged concrete members. Repair of small and medium cracks in concrete: Small and medium cracks in reinforced concrete and masonry structures reduce their strength considerably to bear the design loads. Thus repair of such cracks is necessary to restore the designed strength of members. The repair of small and medium cracks is done by first marking out the critical damaged zones in concrete members. Then these cracks can be repaired by injecting cement grout or chemical grouts or by providing jacketing. The smaller cracks less than 0.75 mm width can be effectively repair by using pressure injection of epoxy. The surface of the member near cracks is thoroughly cleaned. Loose materials are removed and plastic injection ports are placed along the length of crack at an interval equal to the thickness of the structural member. These ports are pl...

Type of work App. Concrete Mix Max. size of aggregates (mm) Water for one cement bag batch (ltr) Total for dry aggregates For aggregates condition from dry to moist Best consistency Small precast work, fence posts, poles, garden furniture and other work of very thin sections 1:2:2 16 20 15 to 16 Soft Storage tanks, cisterns, sewers, well knerbs, watertight work, and columns or other structural parts subjected to high stresses 1:2:3 20 25 19 to 22 Medium Reinforced concrete work, floor slab, beams, columns, arches, stairs etc 1:2.5:3.5 20 32 23 to 27 Medium or soft Ordinary floors, footpaths, drive ways, steps, roads, pavements 1:2.5:3.5 20 23 20 to 23 Stiff Building and basemenot walls, silos, sills, lintels, machine foundations subject to vibration, Bridges, dams, piers, etc exposed to action of water and frost foundation concrete for masonry walls 1:2:4 40 30 23 to 26 Stiff or Medium Culverts, retaining walls, compound walls, ordinary machine bases, etc. 1:3:5 40 34 26 to 30...

Project managers are accountable for the success of a project. They will use their knowledge, skills and tools to ensure that the project requirements are met and that the project is meeting the set goals in a timely manner. The project manager is responsible for planning; executing and closing the projects which means they define the project then build a work plan and manage the budget through the end. They will also manage the teams associated with the project. HERE are step by step procedures to become a project manager. College Education: A college education is essential for obtaining a job as a project manager. The higher the education, the more likely the person will be chosen to be a project lead. A minimum of a Bachelor’s of Science degree in Project Management is generally required to be considered for a project. Project managers may elect to continue their education and obtain a Master’s of Science degree and even a Doctoral degree in project management. Once the degree i...