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This document is a closure to a previous paper titled "Foundation Settlement and Tilt of Millennium Tower in San Francisco, California." The authors respond to comments and questions raised by discussers regarding the design, construction, and analysis of the tower's foundation movements. They emphasize that their goal was to objectively document the data and provide interpretations of the soil deformation mechanisms that caused the settlements. They encourage further investigation and analysis of the case history to advance foundation engineering practices in dense urban environments. [Extracted from the article]

Ground fissure is the most common geological catastrophe phenomenon in Xi'an, posing a major security threat to the currently developing urban cloud rail transit system. In this paper, a 3D-FEM calculation model is established to study the influence of the intersection angles between the hidden ground fissure and the cloud rail on the deformation and failure characteristics of the structure. The findings indicate that the pile foundation is under tension in the main deformation area of the hanging wall of the ground fissure, and the negative friction zone (NFZ) appears below the neutral point (buried depth 18 m for intersection angle 30°). The pile foundation is under compression in the footwall, and the pressure it bears is less than the tensile force sustained by the hanging wall pile, and the NFZ is above the middle point. The NFZ of the pile foundation in the hanging wall and footwall increases as the intersection angle decreases. The pile foundation mainly undergoes vertical settlement, and the horizontal displacement is relatively small. The 3D movement of the pile foundation results in settlement and inclination of the superstructure of the cloud rail simply supported beam bridge, such as the pier and track beam. Therefore, the cloud rail bridge should span the ground fissure at a large angle as far as possible, and 3D adjustable support should be adopted to adjust the offset of the track beam caused by the ground fissure. [ABSTRACT FROM AUTHOR]

Shake table experiments are conducted to assess the potential of the polymer injection technique as a liquefaction countermeasure. A large 2.9 m high (10 ft) laminar soil container on a 3.9×1.85 m (13×6 ft) shake table is employed. Mitigation of liquefaction-induced settlement for a shallow foundation is explored. In a series of two shake table experiments, the system response is studied first without (baseline) and subsequently with polymer injected into the liquefiable stratum. Each test is densely instrumented to provide insights into the dynamic response of the soil and foundation system. Furthermore, cone penetration tests (CPTs) are performed pre- and postinjection to assess the extent of soil improvement. Strong base excitation is imparted by the shake table, resulting in liquefaction and excessive foundation settlement in the original baseline test. In the second test, with the polymer injection countermeasure, a significant reduction is observed in the tendency for liquefaction and the resulting foundation settlement. After this test, careful excavation provided additional insights into the polymer's configuration within the deposit, increasing overall soil relative density, confinement and creating solidified paths for the shallow foundation load toward the lower, more competent stratum. As such, these mechanisms have the potential to allow for: (1) an increase in soil resistance to liquefaction, and (2) a significant reduction in settlement of overlying shallow foundations. [ABSTRACT FROM AUTHOR]

This document is a discussion of the article "Foundation Settlement and Tilt of Millennium Tower in San Francisco, California" by Jonathan P. Stewart et al. The authors analyze the sinking and tilting behaviors of Millennium Tower in San Francisco, focusing on the design of its pile foundation and neighboring excavations. They raise questions about the initial design, the effects of dewatering on the tower, and the settlement calculations and numerical modeling used. The authors also note inconsistencies between the predicted and observed behavior of the tower. Further research is needed to address these issues. [Extracted from the article]

The serviceability limit of the foundation system plays an important role in the safe long-term performance of a building. Under governing load cases in service life, the building foundation system should satisfy the serviceability limit state, i.e., total and differential settlement criteria. This study investigated the distress of a building through foundation performance assessment incorporating the soil–foundation–structure interaction (SFSI) effects. A spatially variable soil model [zonewise, obtained from field observation and electrical resistivity tomography (ERT) study] was used to obtain the settlement of the foundation system. Engineering properties of the subsurface were estimated from the collected soil samples and field tests. ERT result shows the variability of the subsurface layer. A three-dimensional finite-element model of soil, foundations, and structures was developed to estimate the settlement demand of the foundation and structures. The numerical model includes the geometric variability of all the foundations of the building and subsurface variability. Settlement and bearing capacity demand of the foundations were estimated and compared with the standard provisions. Results obtained show that the building foundation system satisfies the serviceability limit of the foundation system under total settlement criteria. However, the differential settlement of the system exceeds the required limit despite considering the SFSI effects, and is one of the major causes of distress to the building. The main contributions of this study also include establishing the spatial variability of the soil layer through ERT and correlating it with the crack zone in the building. [ABSTRACT FROM AUTHOR]

This document is a closure to a case study on ground subsidence caused by the drying effect of Australian native eucalypts. The study highlights the potential for clay soil shrinkage and subsequent damage to structures such as residential buildings, road pavements, and pipelines. Recommendations for addressing the drying effects of trees on nearby buildings vary by country, with the Australian standard AS 2870 providing guidelines for designing footings near trees. The closure also addresses potential queries from practitioners, including the age of the trees, the construction date of the netball court, and the impact of cutting tree roots during barrier construction. The writers express gratitude to Dr. Vishnu Diyaljee for their insights and thank the discusser for their valuable questions and additional insights. [Extracted from the article]

Drainage techniques can be employed to reduce damage of pile rafts in liquefiable ground by decreasing the build-up of excess pore water pressure and maintaining soil stiffness during earthquakes. This paper aims to evaluate the impact of drainage wells on the seismic response of floating piled rafts in fully saturated ground. In practice, floating piles are commonly employed as underpinning elements beneath the raft foundations to reduce undesirable settlement of the raft. Centrifuge experiments were performed on 2 × 2 piled raft foundations with and without drainage wells in mildly sloping ground. Two types of ground involving a uniform sand layer and a uniform sand layer with a superficial gravel layer were reconstructed, whereas the piles were floating within the liquefiable sand. The models were fully instrumented and sine waves were introduced to the models' base at the 80 g centrifugal acceleration. Records of the transducers demonstrate that the drainage wells system significantly decrease the settlement of foundation, dissipation time under dynamic loading by forming closer drainage routes, and excess pore water pressure ratio. In contrary, presence of drainage systems significantly increases the rafts acceleration response, and the bending moment and the axial force of the piles. Results of the piled raft systems in the presence and absence of the drainage wells and the superficial gravel layer are compared with together and also compared with the far-field in terms of the acceleration response, permanent settlement, and excess pore water pressure. [ABSTRACT FROM AUTHOR]

This research project focuses on evaluating the influence of Canadian seismic design provisions on the resistance of reinforced concrete buildings against the differential settlement of their foundation. Three types of moment-resisting frame buildings located in Vancouver, Montreal, and Toronto were designed in accordance with the latest editions of the [NRCC (National Research Council Canada). 2010. National building code of Canada. Ottawa: National Research Council Canada]. The buildings in each location were designed for three span lengths, namely, 4, 6, and 8 m. A total of nine finite-element models were developed using SAP2000 version 20 with structural element nonlinearity being represented through plastic hinges at the ends of beams and columns. A nonlinear analysis was performed on each model by gradually subjecting a center column to a settlement of 100 mm. The analysis reveals that buildings with a shorter span (e.g., 4 m) length are more vulnerable to settlement-induced damage than buildings with longer spans (e.g., 8 m). Failure of the settling column occurs at settlements that exceed the range of maximum allowable differential settlements prescribed in the Canadian Foundation Engineering Manual. [ABSTRACT FROM AUTHOR]

The San Jacinto Monument was built in 1936 to celebrate the 100 year anniversary of the battlefield victory that gave Texas its freedom. Ray Dawson was in charge of the foundation design and decided to instrument the foundation to monitor the settlement of the Monument. The settlement has been recorded since 1936 and provides a very valuable long-term record. This settlement and other geotechnical data were studied and reported by Briaud and his co-authors in 2007. That study was based on data available at the time, which was primarily from a 61-m-deep boring in 1953. In 2007, Fugro and Texas A&M University drilled a new boring with sampling to a depth of 78 m, conducted in situ tests to 36 m, and laboratory tests on the samples recovered. Updated settlement calculations are provided using this new data; they show reasonably good agreement with modern settlement techniques. One of the issues possibly affecting the settlement readings is the subsidence of the ground surface, which can reach 3 m in that area of Houston. A second part of this article presents calculations and numerical simulations to evaluate the influence of subsidence on the recorded settlement of the Monument. It is shown that the true settlement of the SJM is 295 mm while the measured settlement is 328 mm. The reduction is due to the different influence of the subsidence on the settlement of the shallow benchmark and of the Monument. [ABSTRACT FROM AUTHOR]

Ground movements observed during foundation installation and basement construction of a residential 53-story RC tower are presented. The One Museum Park West building is located in Chicago, Illinois, and was developed using a combination of bottom-up methods, used for the construction of a central concrete core of the building, and top-down methods to build five levels of basements. The excavation extended 13-15 m below grade and was made through soft to medium-stiff clays. The building was supported by drilled shafts and a perimeter wall formed by secant piles that transitioned to tangent piles below the bottom of the cut. The system was laterally braced with RC floor slabs structurally connected to the secant pile walls and the RC core. Field performance data were collected by means of settlement points and inclinometers located close to the walls on two sides of the excavation. The construction sequence and attendant ground movements during each main activity are summarized. As much as 160 mm of settlement was recorded in the adjacent streets throughout construction. Wall and foundation installation accounted for approximately 35% of the total settlements during construction, whereas top-down construction of the basement resulted in approximately 40% of the total settlements. These data emphasize the importance of considering all construction activities when making predictions of ground movements adjacent to deep supported excavations. [ABSTRACT FROM AUTHOR]