A tri-layer steel reinforced concrete (S3RC) building structure comprises a steel frame, at least one steel shell layer, multiple rebars, and a concrete. The steel shell layer is mounted on the steel frame. The rebars are connected to the steel frame and located at one side of the steel shell layer. The concrete is mounted at the side of the steel shell layer and embeds the rebars. With the steel shell layer and/or the steel frame cover the concrete and the rebars, a tensile resistance of the concrete may be enhanced from the exterior, increasing the earthquake resistance. If the earthquake occurs and the concrete is shattered, the broken pieces may be covered by the steel shell layer rather than fall apart, avoiding collapse of the overall structure. Besides, the steel shell layer can also protect the concrete from being affected by the atmosphere and moisture, preventing the concrete from bulging and weathering.

Environmentally friendly concrete compositions and methods thereof are disclosed. For example, a method for producing an environmentally friendly concrete installation can include mixing cement, one or more locally sourced pozzolans, and one or more locally sourced aggregates to produce a dry concrete mixture. At least one fine aggregate or coarse aggregate of the dry concrete mixture is a locally sourced aggregate of the one-or-more locally sourced aggregates for a reduced carbon footprint. The method can include hydrating the dry concrete mixture with water to make a pourable concrete mixture. The method can include pouring the pourable concrete mixture into a formwork to produce a poured concrete form. The method can include allowing the poured concrete form to cure to produce the concrete installation. The reduced carbon footprint of the concrete installation is relative to that of a similar concrete installation produced without the one-or-more locally sourced pozzolans or aggregates.

A number of modular preformed skeletal steel panels are mounted side by side in a row on a building structure to form a composite panel assembly on the building structure. Each modular preformed skeletal steel panel comprises two mesh layers, namely a bottom mesh layer and a top mesh layer supported spaced-apart in parallel planes by intermediate spacers extending between the layers. The bottom layer has a plurality of spaced-apart outwardly projecting splice bars for interengagement with an adjacent preformed skeletal steel panel in the panel assembly thus facilitating interengagement of the modular preformed skeletal steel panels in the composite panel assembly. Each spacer comprises a cross member engaged with the top layer and having outwardly extending legs at opposite ends of the cross member. A lower end of each leg terminates in a foot which engages with the bottom layer. The cross member, legs and feet are all mutually perpendicular.