MBR Construction Plc

LIQUIFACTION Soil liquefaction is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading. Liquefaction and related phenomena have been responsible for tremendous amounts of damage in historical earthquakes around the world. Liquefaction occurs in saturated soils, that is, soils in which the space between individual particles is completely filled with water. Prior to an earthquake, the water pressure is relatively low--the weight of the buried soil rests on the framework of grain contacts that comprise it. However, earthquake shaking can disrupt the structure, the soil particles no longer support all the weight, and the groundwater pressure begins to rise. The soil particles can move farther, and become entrained in the water--the soil flows. Liquefied soil will force open ground cracks in order to escape to the surface. The ejected material often results in flooding and may leave cavities in the soil. Whether and where liquefaction will take place depends on many factors. These include the degree of saturation, the grain size distribution and consistency at a site, the strength, duration, and frequency content of the shaking and even the grain shape and depth of soil. There is much active research into the mechanisms of liquefaction, because its effects can be so severe yet its process remains imperfectly understood. consequences to structures and utilities of earthquake-induced liquefaction include: 1) Non-uniform and differential settlement of structures often resulting in cracking. 2) Loss of bearing support 3) Flotation of buried structures such as sewer lines, tanks, and pipes. 4) Strong lateral forces against retaining structures such as seawalls. 5) Lateral spreading (limited lateral movement) 6) Lateral flows (extensive lateral movement) #earthquakeengineering #Geotechnicalengineering #Groundresponseanalysis #structuralengineering #liquifactionassesment

Latest news from Shoring Construction in Addis Ababa with soil nailed wall System executed by MBR Engineering and Construction Plc. We are excited to announce the successful completion of a significant project constructing a 1400sq.m soil nailed wall adjacent to the main road from Jemo-Bisrate Gebriel Square and the border with St michael Church. 🔧 Project Highlight: - Location: Addis Ababa - Method: Drill and Grout soil nail wall - Contractor: MBR Engineering and Construction Plc. 🚀 Project Impact: - Creates a stable working environment for underground construction. - Significantly saves on the economy compared to ordinary piling methods. - Demonstrates innovative engineering solutions. Congratulations to those who participated in the project for their exceptional work and dedication in this project! hashtag #SLOPESTABILITY hashtag #CivilEngineering hashtag #Infrastructure hashtag #SOILNAILING hashtag #EngineeringExcellence hashtag #InternationalCollaboration hashtag #Innovation hashtag #AddisAbaba hashtag #SuccessStory

Shootcrete work An automated machine applying sprayed concrete for structural support in a tunnel construction project. Sprayed concrete, or shotcrete, is a crucial technique in tunnel construction, applied using an automatic machine for enhanced precision and efficiency. The process involves projecting a mix of cement, aggregate, and water onto tunnel surfaces at high velocity. This method provides immediate ground stabilization, crucial for the safety and speed of tunnel construction. The use of automated machines ensures consistent application, reduces labor costs, and enhances worker safety. The rapid setting properties of sprayed concrete minimize construction time while offering robust and durable support for tunnel walls, adaptable to complex shapes and profiles.

Piles and Pile Foundation Pile foundation is defined as a series of columns inserted into the ground to transmit loads to a lower level of sub-soil. A pile is a long cylinder made up of a strong material, such as concrete. Piles are pushed into the ground to act as a steady support for structures built on top of them. Piles transfer the loads from structures to hard strata, rocks, or soil with high bearing capacity. normal soil conditions, pile foundations are used to withstand elevations such as offshore platforms, foundations below groundwater levels, or basic transmission towers. Pile foundations are also used in soft soil to withstand horizontal loads, such as wind power and earth-quake bending forces. Soils which are easy to grow and shrink and which are sensitive to soil moisture change also need a pile foundation. In addition, construction works on water such as jetty and bridge piers, it also needs a pile foundation. Piles are relatively long and slender members which are used to transmit the load to deeper soil or rock of high bearing capacity avoiding shallow soil of low bearing capacity. The main types of materials used for piles are wood, steel, and concrete. Piles made from these materials are driven, drilled, or jacked into the ground and connected to pile caps. Depending upon type of soil, pile material and load transmitting characteristic, piles are classified accordingly. Piles are also sometimes used to resist heavy uplift and lateral forces. Piles are normally used for (i) to carry structure loads into or through a soil stratum, (ii) to resist uplift or overturning forces, (iii) to control settlements when spread footings are on marginal or highly compressible soil, (iv) to control scour problems on bridge abutments or piers, (v) in offshore construction to transmit loads through the water and into the underlying soil, and (vi) to control earth movements, such as land-slides. Piles are used (i) when the existence of a suitable bearing layer cannot be obtained, i.e., the soil under the structure is not functioning well or in other words is unable to bear the load caused by the structure when the shallow foundation is used, (ii) when there is inadequate bearing capacity for shallow foundations, (iii) the compressibility of soil causes large sedimentation when the shallow foundation is used, (iv) when the distribution of soil beneath the surface is not uniform, (v) for the purpose of preventing the action of gravity from beneath the surface such as hydrostatic action, (vi) for getting a strong-strata in the excavation work, (vii) for the prevention of uplift forces, and (vii) for reducing excessive settlement.

Mechanically Stablized Earth Wall (MSE Wall ) A Mechanically Stabilized Earth (MSE) retaining wall is a composite structure consisting of alternating layers of compacted backfill and soil reinforcement elements, fixed to a wall facing. The wall facing is relatively thin, with the primary function of preventing erosion of the structural backfill. Soil retaining walls are designed to bring stability to natural slopes in construction projects. Stabilization for MSE retaining walls comes from the interaction between the backfill and soil reinforcements, involving friction and tension. The wall facing is relatively thin, with the primary function of preventing erosion of the structural backfill. The result is a coherent gravity structure that is flexible, stable and can carry a variety of heavy loads. The properties and materials of the three major components can vary, and a mechanically stabilized earth engineer must choose the most efficient combination of construction materials based on the wall’s design criteria, such as wall height and service life. Each of these elements works together to create a stabilized retaining wall. Facing elements are modular precast concrete panels or wire mesh. Each facing type offers different advantages when considering criteria such as aesthetics, durability, construction procedure, and expected settlement. Soil reinforcements are typically steel or geosynthetic, in the form of strips or ladders. All soil reinforcement options have unique characteristics for pullout and tensile capacity, corrosion, and durability. Select backfill allows for reliable construction and performance of the wall, in which the gradation, plasticity, electrochemical properties, and overall durability should be closely analyzed. It can be obtained on site, or from a distributor.

Soil nail defnition of soil nail incorporates the following fundamental elements: resisting mechanisms, materials, construction methods, and construction Quality Control (QC) and Quality Assurance (QA). Soil nails are reinforcing, passive elements that are drilled and grouted sub-horizontally in the ground to support excavations in soil, or in soft and weathered rock that: • Contribute to the stability of earth-resisting systems mainly through tension as a result of the deformation of the retained soil or weathered rock mass. • Transfer tensile loads to the surrounding ground through shear stresses (i.e., bond stresses) along the grout-ground interface. • Develop resistances that can be estimated with established design procedures. • Have long-term, demonstrable corrosion protection to ensure adequate, long-term performance of the system. • Interact structurally with the facing of the excavation. • Are load-tested according to prescribed methods. • Are routinely subject to construction QC/QA according to established procedures. Reinforcing elements that are post-tensioned, even if installed adjacent to conventional soil nails, are referred to as ground anchors. As stated in the definition, load transfer to and from the surrounding ground develops through shear stresses acting along the grout interface of the soil nail. As the reinforced-soil block deforms, shear stresses develop at the grout-ground interface. Because the retained soil deforms toward the excavation, soil nails undergo extension resulting in axial tensile forces in the soil nail tendon. The axial tensile load in the tendon increases from the nail head to a maximum value; then decreases as the soil nail transfers load to the surrounding ground. The tensile resistance of the soil nail tendon and the pull-out resistance of the soil nail are the main resisting mechanism.

Sheet pile wall Sheet piling can be used to provide permanent foundations, permanent or temporary retaining walls and as extremely strong shuttering when a poured concrete foundation or retaining wall is required. Sheet piling can form the basis for an underground structure such as a basement or underground car park the difference between a sheet pile and a retaining wall :- Sheet piles are used for temporary earth retention, while retaining walls provide long-term support.

Bored cast insitu pile Bored piles are steel reinforced concrete elements cast in situ used to transfer high loads through soil to deeper, more competent soil or rock stratum. Constructed with conventional rotary kelly bar plant, the drilling tooling is selected to suit the nature of the soils to be excavated. image below shows bored cast insitu pile used for shoring work.

Biggest pile foudation project in dam work at akal Dul HE Project (1000 MW) which is proposed on river Marusudar, a tributary of river Chenab in district Kishtwar of J&K state and is about 45 kms from Kishtwar. The project envisages construction of a 167 m high Dam, an underground Power House with 4 units of 250 MW each.