Reducing Carbon Emissions by Combined Pile-Raft Foundations for High-Rise Structures

Regarding the impact of construction processes on the environment, the reduction of CO2 has an important role. The production of materials e.g. reinforced concrete, and the construction of structures consume large amounts of energy, which leads to a large emission of CO2. The target is the reduction of the amount of construction material used and of the energy consumed for construction. For this, the structures have to be optimized regarding the geometry considering the requirements of the stability, serviceability, and durability. Also, foundation systems of high-rise buildings can be optimized regarding CO2 emission. For the optimization, three parts have to be considered. The first part is the detection of the real load-deformation behavior of a foundation element. This can be reached by large-scale load tests in situ. The second part is to use the hybrid foundation system Combined Pile-Raft Foundation (CPRF), which combines the bearing capacities of the raft and of the piles. The third part is the realistic prediction of the load-deformation behavior of the foundation. For this three-dimensional, nonlinear calculations using the Finite-Element-Method (FEM) are necessary. The contribution explains the three parts and shows the application in engineering praxis, including case studies

Safety Assurance for Challenging Geotechnical Civil Engineering Constructions in Urban Areas

Safety is the most important aspect during design, construction and service time of any structure, especially for challenging projects like high-rise buildings and tunnels in urban areas. A high level design considering the soil-structure- interaction, based on a qualified soil investigation is required for a safe and optimised design. Due to the complexity of geotechnical constructions the safety assurance guaranteed by the 4-eye-principle is essential. The 4-eye-principle consists of an independent peer review by publicly certified experts combined with the observational method. The paper presents the fundamental aspects of safety assurance by the 4-eye-principle. The application is explained on several examples, as deep excavations, complex foundation systems for high-rise buildings and tunnel constructions in urban areas. The experiences made in the planning, design and construction phases are explained and for new inner urban projects recommendations are given

Design and Construction of Deep Foundation Systems and Retaining Structures in Urban Areas in Difficult Soil and Groundwater Conditions

Economic and environment-friendly design focuses on a reduction of construction material used, construction time spent and energy consumed within the buildings construction and service time. Regarding deep foundation systems and retaining structures for excavations this paper highlights the important role of enhanced geotechnical design and independent quality assurance by means of the 4-eye- principle

Realistic Modelling of Soil-structure Interaction for High-rise Buildings

AbstractFor a save design and construction and the technical and economic optimisation of deep foundation systems a realistic modelling of the soil-structure interaction is necessary. Especially for the hybrid deep foundation system Combined Pile-Raft Foundation (CPRF) this has to be considered. Based on an adequate soil investigation, in-situ pile load tests and a high-level design using the Finite-Element-Method (FEM) it is possible to design complex foundation systems for high-rise buildings even in soft soil conditions. For guarantee of the ultimate limit state (ULS) and the serviceability limit state (SLS) an independent peer review and the application of the observational method is necessary. The paper explains some special aspects of the optimisation process of the design and presents several projects from engineering practice, where the CPRF has been successfully applied

Experimental Study of the Modulus of Deformation Determined by Static and Dynamic Plate Load Tests

Soil, or soil structure modulus of deformation, is one of the main design parameters for road engineering and traffic infrastructure design of, for example, highways, railways, runways and embankments. It is also the main soil improvement criterion. When creating any road structure with codified design resistance, one employs structural layers of certain thicknesses and modulus of deformation. Both values need to satisfy the minimum values in accordance with codified requirements. This paper analyzes correlations for the widely applied in engineering practice methods to determine the soil stiffness. The static test methods acknowledged to be exact enough for determining the modulus of deformation for the primary and secondary loadings. As dynamic test methods require significantly less time and financial resources, they are widely accepted in engineering practice. The dynamic methods determine only the dynamic modulus of deformation. Design practice aims to relate it with the static modulus of deformation of the secondary loading. Many countries propose codified correlations, with differing levels of conservatism, to convert the dynamic modulus of deformation into the static one. Developed correlations between the results of the static plate load test and the dynamic plate load tests processed from own test results of different soils are presented and a comparative analysis with other proposed correlations is given