A building foundation structure includes a ground improved body obtained by improving a surface layer ground, and foundation concrete placed on the ground improved body. A bottom surface of a foundation concrete located below a building pillar has a four-or-more-sided polygonal shape smaller than the plan shape of the foundation concrete, and a part of the lower surface of the foundation concrete other than the bottom surface is a slope surface connecting the bottom surface and the plan shape. Since the stress from the foundation is transferred to the lower ground in its broader range, the stress transferred to the lower ground can be reduced. In addition, since the placing amount of the foundation concrete is reduced, the construction cost can be reduced.

A machine, method and system for installing helical foundation piers that sues a driving tamper connected to a rotary tool to drive helical piers into the ground. Once the pier reaches the target depth, the tamper is decoupled, and counter rotated away from the pier. While it is withdrawn the soil between the driven and pier and the driving tamper is compressed by intermittent downward action of the tamper.

A machine, method and system for installing helical foundation piers that sues a driving tamper connected to a rotary tool to drive helical piers into the ground. Once the pier reaches the target depth, the tamper is decoupled, and counter rotated away from the pier. While it is withdrawn the soil between the driven and pier and the driving tamper is compressed by intermittent downward action of the tamper.

Various examples are provided for in situ growth of subsurface structures using bioinspired mineralization. In one example, among others, a method for growth of a subsurface structure includes introducing a first aqueous mineral salt reactant and a second aqueous mineral salt reactant comprising a polymeric additive into a soil substrate. The first and second aqueous mineral salt reactants can combine to form a polymer-induced liquid-precursor (PILP) phase that initiates in situ mineralization in the soil substrate. Solidifying the mineralization can form a subsurface structure in the soil substrate. Multiple applications of aqueous mineral salt reactants can be introduced to adjust the thickness of the mineralization or for layers of coatings.

Various examples are provided for in situ growth of subsurface structures using bioinspired mineralization. In one example, among others, a method for growth of a subsurface structure includes introducing a first aqueous mineral salt reactant and a second aqueous mineral salt reactant comprising a polymeric additive into a soil substrate. The first and second aqueous mineral salt reactants can combine to form a polymer-induced liquid-precursor (PILP) phase that initiates in situ mineralization in the soil substrate. Solidifying the mineralization can form a subsurface structure in the soil substrate. Multiple applications of aqueous mineral salt reactants can be introduced to adjust the thickness of the mineralization or for layers of coatings.

A wind turbine foundation comprising a concrete support slab having a horizontal rebar grid therein, a concrete pedestal integral with the support slab and having vertical post tensioning elements therein and a plurality of concrete ribs on top of and integral with the support slab and integral with the pedestal, the ribs having rebar therein and extend outwardly from the pedestal, the pedestal, slab and ribs are connected to each other to form a monolithic foundation. The foundation design reduces the weight and volume of materials used, reduces cost, and improves heat dissipation conditions during construction by having a small ratio of concrete mass to surface area thus eliminating the risk of thermal cracking due to heat of hydration.

A wind turbine foundation comprising a concrete support slab having a horizontal rebar grid therein, a concrete pedestal integral with the support slab and having vertical post tensioning elements therein and a plurality of concrete ribs on top of and integral with the support slab and integral with the pedestal, the ribs having rebar therein and extend outwardly from the pedestal, the pedestal, slab and ribs are connected to each other to form a monolithic foundation. The foundation design reduces the weight and volume of materials used, reduces cost, and improves heat dissipation conditions during construction by having a small ratio of concrete mass to surface area thus eliminating the risk of thermal cracking due to heat of hydration.

A wind turbine foundation comprising a concrete support slab having a horizontal rebar grid therein, a concrete pedestal integral with the support slab and having vertical post tensioning elements therein and a plurality of concrete ribs on top of and integral with the support slab and integral with the pedestal, the ribs having rebar therein and extend outwardly from the pedestal, the pedestal, slab and ribs are connected to each other to form a monolithic foundation. The foundation design reduces the weight and volume of materials used, reduces cost, and improves heat dissipation conditions during construction by having a small ratio of concrete mass to surface area thus eliminating the risk of thermal cracking due to heat of hydration.

A wind turbine foundation comprising a concrete support slab having a horizontal rebar grid therein, a concrete pedestal integral with the support slab and having vertical post tensioning elements therein and a plurality of concrete ribs on top of and integral with the support slab and integral with the pedestal, the ribs having rebar therein and extend outwardly from the pedestal, the pedestal, slab and ribs are connected to each other to form a monolithic foundation. The foundation design reduces the weight and volume of materials used, reduces cost, and improves heat dissipation conditions during construction by having a small ratio of concrete mass to surface area thus eliminating the risk of thermal cracking due to heat of hydration.

One aspect of the invention provides a structure including one or more strut tubes adapted and configured to receive and hold a granular material. The one or more strut tubes further include compression means for applying at least compression to the granular material after loading. Another aspect of the invention provides a method of erecting a structure. The method includes: inflating one or more strut tubes with a fluid; displacing the fluid with granular material; and compressing the granular material.