Journal of Architecture and Construction Volume 3, Issue 3, 2020, PP 1-16 ISSN 2637-5796 Best Practice Building Integration Methods along Slopes (15% To 65% Gradient) N Okigwe Zone, Southeastern Nigeria Christopher Irehie1*, Napoleon Imaah2, and Patrick Youdeowei3 1Institute of Geosciences and Space Technology (IGST), Rivers State University, Nkpolu/Oroworukwo, Port Harcourt, Rivers State, Nigeria 2Department of Architecture, Rivers State University, Nkpolu/Oroworukwo, Port Harcourt, Rivers State, Nigeria 3Institute of Geosciences and Space Technology (IGST), Rivers State University, Nkpolu/Oroworukwo, Port Harcourt, Rivers State, Nigeria *Corresponding Author: Christopher Irehie, 1Institute of Geosciences and Space Technology (IGST), Rivers State University, Nkpolu/Oroworukwo, Port Harcourt, Rivers State, Nigeria ABSTRACT To create integral buildings along slopes require that the land form and topography of the slope be incorporated into the architectural designs and construction plans from the outset. The relevance of the study was informed by the need to bring man closer to natural environment visibly manifest in the form of slopes. The study, through data collection, analyses, and concept development determined five architectural floor methods of building integration along slopes. Different building integration methods fit into slopes of different gradients and angles which are classified by percentage characteristics as: Split level (4 – 6% slope); Build up above the slope (6 – 10% slope); Build into the slope (10 – 16% slope); Cut and fill (16 – 25% slope); and Multi-level (25% slope and above). For ease of analysis, the architectural floor methods of integration were catalogued into A, B, C and D systematic order for appropriate results presentation relative to slope factors. Keywords: Building integration, Concept, Slopes gradient, Slope angle, Slopes profile, Architectural floor method. INTRODUCTION slope site, has to be properly considered architecturally from the perspective of the The research on best practice building slopes gradient and angles (Armor and Snell, integration methods along slopes took into 2019; Fadamiro and Ogunsemi, 2020; Green account, factors which impact the surfaces of sheet, 2019). The topography of Okigwe Zone is slopes; and which can likely lead to building hilly and undulating compared to the rest of Imo failure, to proffer architectural solution through State with relatively flat and low-lying relief. design concept and building components Few hilltops around Okigwe Zone reach 300m, development for the creation of adaptable while the average height of the crest lies buildings that are well integrated along slopes. between 120 and 180m above sea level. Steep Rahn (2020); Emma and Gary (2019) stated slopes and gully erosion are principally found in that, it is most important to consider not only the vicinity of Umuduru, Okigwe town, and Etiti what can safely be done with a given piece of axes. land, but the optimum use to which the land can be put. New buildings on slopes should involve Before the plans of any building can be drafted, special foundations that are in accordance to the the design of the building components and their most appropriate architectural floor method of relationship to one another and to the integration along slopes of different slope environment must be determined. It is against angles. In simple terms, the architectural design this background that this research determined has to make sure that the whole building will not the different architectural floor methods of slide down the slope. One advantage of slopes is buildings integration according to slope angle or that they invariably come with an interesting percentage of slope, using the Okigwe Zone view, but to achieve this view, the foundation contour map profiles. Different building type and floor method of integration into the integration methods go well for different slope Journal of Architecture and Construction V3 ● I3 ● 2020 1 Best Practice Building Integration Methods along Slopes (15% To 65% Gradient) N Okigwe Zone, Southeastern Nigeria angles. Consequently, according to Ahmadu the man built environment and landscapes begin (2020), it is critical that buildings be conceived to deteriorate. This menace continues to grow in and designed with the utmost care and intensity and seriousness for as long as the sensitivity peculiar to the site so it indeed fulfills building is not properly integrated along the its vital role in the overall environment. slope profile using the most appropriate architectural floor method for the slope angle or THE IMPORTANCE OF THE STUDY gradient. The successful integration of any building along Nevertheless, the determination in this study is a slope should be borne out of a clear-cut slope to pursue change in the negative attitude site inventory and inventory analysis resulting towards building along slopes, by outlining from the exercise of several professionals who standards for best practice building integration are coordinated by the Architect, and they methods along slopes of different gradient (15% include: the Surveyor – who makes graphical to 65% and more). The study is important for representation of the site (including contours) the following reasons: and its area features on paper; the civil and geological engineers – who uses the information The need to outline standard for building from the slope soil test investigation and the integration methods along slopes of architectural drawings to design appropriate different slope angles to avoid failure. foundation and structure for the building. The need to utilize slopes for sustainable Bergsma (2018) in his analysis of the influence housing development amid scarce land of relief on erosion outlined seven classes of commodity. slopes that are related to those of soil survey. The need to develop an environmental - Nearly level 0 – 2% friendly approach towards the integration of -Gently undulating 2 – 4% buildings along slopes for sustainability and strength in erosion prone areas. -Steeply undulating 4 – 6% The results of the research provides -Gently rolling 6 – 10% parameters for requisite architectural design -Steeply rolling 10 – 16% standards for buildings interation along slopes. -Hilly 16 – 25% STUDY OBJECTIVES -Steep 25% - ? There are five types of building integration Whereas Brady and Weil (2019) advised that methods that can be used successfully along possible failure should be investigated slopes as identified by the study. The type particularly on a site with more than 15 percent chosen depends upon many factors. If a slope (15 meters of rise over 100 meters of basement is desired, the foundation forms the horizontal distance); on a site with much steeper basement wall. If a house is to be built over a slopes above or below it; or in any area where crawl space, the foundation may be masonry erosion is a recognized problem. Slope is wall or piers. typically expressed as percentage, an angle, or ratio. The average slope of a terrain feature can A curtain wall may become part of a foundation. conveniently be determined from contour lines In areas where soil does not offer sufficient on a topographic map (Philip et al., 2018; Paul, support for usual foundations, pilings must be 2018; Singh, 2020). used to support the foundation wall. Whatever may be the soil condition of the site, it is up to It is noteworthy that any careless development the engineer to come up with a foundation on slopes vulnerable to increase in solution that will suit the Architect’s concept for environmental risks would equally give birth to floor method of integration. unfavourable environmental consequences. The study of best practice building integration However, it is a must that the specified methods along slopes in the built environment is foundation design solution must be in agreement important to the generality of the environment in with the architectural design floor method of that the hazards of building failure are not integration. Figure 1 to Figure 4 below, shows limited to the soil structure. No sooner a the different architectural floor methods of building gives signs of failure on slopes, than building integration along slopes. The 2 Journal of Architecture and Construction V3 ● I3● 2020 Best Practice Building Integration Methods along Slopes (15% To 65% Gradient) N Okigwe Zone, Southeastern Nigeria determination of the most suitable building slope gradient up to 65% and more can warrant integration method on slopes of different slope the introduction of basement floors in the design angles is a function of how “gently undulating” concept. Stepped buildings cut at intervals along or “steep” the slope gradient might be. In some hilly slopes, is another integration option, instances where the slope is gentle, Architects though not advisable in areas with leachate soil design to suite the site with split levels. Other like Okigwe Zone. A typical example of times, when the slope gradient is steep, the “stepped buildings” is found in colliery camp, design principle of “cut and fill” may be Enugu State, south-eastern Nigeria. administered in the design concept. Steeper Figure1. Build up above the Slope This method involves suspended floors, some work below floor level. This method will additional costs, and the need for very careful improve view, especially from the balcony. landscaping to conceal the large area of masonry Figure2. Build into the Slope Journal of Architecture and Construction V3 ● I3 ● 2020 3 Best Practice