Patent ID: 6117521
Filing Date: 2000-09-12
Classification: E04G,Y10T

Abstract:
A plastic, lightweight formwork for concrete, which is an integrally molded article of a crosslinked polymer obtained by mixing a monomer solution A of a metathesis polymerizable cycloolefin containing a catalyst component of a metathesis polymerization catalyst system and a monomer solution B of a metathesis polymerizable cycloolefin containing an activator component of a metathesis polymerization catalyst system, injecting the mixture into a mold and subjecting the mixture to polymerization and a crosslinking reaction in the mold, wherein:(1) the formwork has a rectangular plate having a front surface and having a longitudinal length of 1,000-4,000 mm, a lateral length which is 1/2-1/10 of the longitudinal length and a thickness of 3-10 mm, and a reverse surface of the plate has a frame surrounding the plate and 3 to 6 crosspiece ribs are longitudinally formed on the reverse surface, the frame surrounding the plate having a thickness of 5 to 20 mm and a height of 40 to 100 mm,(2) the crosspiece ribs integrally and longitudinally formed on the reverse surface of the plate have the total thickness of 1/10-1/30 of the lateral length of the plate and the height equivalent to the height of the surrounding frame and are joined to the surrounding frame at both ends thereof, and(3) the formwork has a plurality of small reinforcing ribs on at least part of the reverse surface thereof, and the small ribs satisfies the following characteristics (i)-(v),(i) 2.5.ltoreq.h.ltoreq.5(ii) a/100.ltoreq.H.ltoreq.a/5(iii) 5.ltoreq.i.ltoreq.20(iv) 0.ltoreq..theta..ltoreq.45, and(v) each small rib has such a length that its both ends are connected to the neighboring longitudinal crosspiece ribs or to a longitudinal crosspiece rib and a longitudinal frame,wherein h is an average thickness of each small rib in the unit of mm provided that the average thickness refers to the thickness of each small rib measured at a point as high as 1/2 of the small-rib height, H is a total thickness of the small ribs located in one column in the longitudinal direction in the unit of mm, a is a length of the formwork in the longitudinal direction of the formwork in the unit of mm, i is a height of each small rib in the unit of mm, and .theta. is a smaller angle of angles formed between the length direction of each small rib and a direction in parallel with the lateral direction of the formwork.