A tower/frame structure (100, 150, 160) of interconnected columns (112) and beams (114, 116) (which may be used in a cooling tower) and novel columns (112), beams (114, 116) and connection mechanisms are provided. In one embodiment, a column (112) and a beam (114, 116) are constructed of pultruded composite fiber-reinforced plastic (FRP) materials. The beam (114, 116) includes two sidewall extensions or flanges (310, 312, 410, 412) (each having one or more attachment apertures (308, 408)) at one end and which are integral with the beam (114, 116) for connection to the column (112) (having one or more corresponding attachment apertures (208)). The dimension/spacing between the inner walls of the two flanges (310, 312, 410, 412) substantially equals or is slightly larger than the outer dimension of the column (112). The attachment holes (208 ,308, 408) are aligned and a fastener (330) is inserted through the extensions (310, 312, 410, 412) and column (112) for attaching the column (112) and beam (114, 116). The C-shaped end of the beam (114, 116) substantially conforms to the cross-sectional shape and dimensions of the column (112).