Author: Mezie Ethelbert

Reading Time: 4 minutes The deck and girder is one of the commonest type of bridges. In the bridge, girders, which are special beams are used to support the deck slab, where the vehicles move. The deck also includes the road lanes, medians, sidewalks, parapets or railings and other items like drainage and lighting. The design of the deck and girder bridge begins with the estimation of the design moments both in X and Y-directions. The deck moments would be estimated for both the live loads and the dead loads using the M. Pigeaud’s method. As noted in previous post on functional design, a…

Reading Time: 3 minutes Spot height is an exact point on a map or plan with an elevation recorded beside it. In other words, it represents height above a given datum. The Earth’s surface is naturally uneven (undulating or slopy). In construction works such as framed structures, it is expected that the foundation of columns should be at the same depth especially for undulating grounds irrespective of the nature of the ground surface. Undulating surfaces or fairly uneven surface is applicable here because in slopy grounds, foundations need to be stepped to minimize cost of excavation and materials. If the footing bases are not…

Reading Time: 3 minutes Setting-out is often seen as a reverse process of surveying. Setting-out means transferring the building or structure design onto the land itself so that builders or site engineers can follow it during construction. It is needed to guide construction process and achieve accuracy. To achieve this aim, the new structure set-out must be correct in all 3-dimensions both relatively and absolutely. That is, it must be of the same correct size, in the correct plan position and at the correct level. To minimize cost in setting out, once it is started, it must proceed quickly with little or no delay.…

Reading Time: 4 minutes Road classification is a technique for grouping roads according to their purpose and location etc.. This strategy aids in organizing and prioritizing road maintenance and construction, as well as improving the effectiveness and safety of transportation. Before a road is classified, it is necessary to consider the factors that affect road classification systems. Factors that Affect Road Classification Systems There are about five (5) factors that influence the classification of roads in any system. These include: i. Trip purpose: This refers to the reason why people use the road either for access or mobility. ii. Trip length: This refers to…

Reading Time: 4 minutes The protection of water ingress into the subgrade (foundation) of pavement is of utmost importance to the highway Engineer because water is an enemy of pavement especially those made with soils that have appreciable amounts of fines. If water is allowed to enter and soak the subgrade, it weakens the strength of the compacted soil under load and the pavement would soon fail. In this post I would show the three (3) ways water can enter and leave road subgrade and how to control them. Three (3) notable ways water can subgrade of pavement include: 1. Seepage from high ground:…

Reading Time: 3 minutes One may have wondered why piles are most times placed in groups to bear loads instead of singly. Is it not possible to use single piles to carry column loads? The reasons for these are somewhat interwoven. Pile groups are commonly used for driven piles more than bored piles because driving errors could produce eccentricity on the pile which could affect the pile bearing capacity. When piles are placed in group, the piles would complement each other and offset this weakness. On the other hand, when piles are placed in group, the individual capacities of the piles are reduced due…

Reading Time: 4 minutes Piles are one of the commonest types of deep foundations. A foundation is said to be a deep foundation if the the depth of footing (Df) is greater than 15 times the breadth of the footing. That is Df ˃ 15B. Other common types of deep foundations are pier foundation and caissons/well foundation. Piles can be classified under different basis such as: Material of construction: Timber piles, concrete piles, steel piles Functions: End bearing piles, friction piles, compaction plies, tension piles, raker piles Method of construction: Displacement piles (driven or driven and cast-in-situ), non-displacement or replacement piles (driven and cast-in-situ…

Reading Time: 10 minutes CSC Orion is one of most widely used reinforced concrete design softwares in the world. Even though its use is limited only to reinforced concrete design, it has the unique feature that it integrates design with detailing in one suite unlike some analysis and design softwares. Foundation design in Orion comes behind structural analysis as the loads from the superstructures need to be fully and accurately transferred to the foundation in order to determine the accurate cross-section elements. Many users of Orion can quickly find the pad foundation design icon in Orion which is the simplest type of foundation handled…