24.12.2014 Views

Earthquake Engineering Research - HKU Libraries - The University ...

Earthquake Engineering Research - HKU Libraries - The University ...

Earthquake Engineering Research - HKU Libraries - The University ...

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

277<br />

TABLE 3<br />

SUMMARY OF STRUCTURES CONSIDERED<br />

Model<br />

N35<br />

N80<br />

N100<br />

N120<br />

N80R<br />

N100R<br />

N120R<br />

N80RS<br />

N100RS<br />

N120RS<br />

f c (MPa)<br />

35<br />

80<br />

100<br />

120<br />

80<br />

100<br />

120<br />

80<br />

100<br />

120<br />

Beams<br />

415<br />

415<br />

415<br />

415<br />

600<br />

700<br />

800<br />

600<br />

700<br />

800<br />

Columns<br />

415<br />

415<br />

415<br />

415<br />

415<br />

415<br />

415<br />

600<br />

700<br />

800<br />

f y (MPa)<br />

Shear Wall<br />

415<br />

415<br />

415<br />

415<br />

415<br />

415<br />

415<br />

600<br />

700<br />

800<br />

Hoops<br />

415<br />

415<br />

415<br />

415<br />

415<br />

415<br />

415<br />

600<br />

700<br />

800<br />

Remarks<br />

Basic Model Structure<br />

Equivalent Stiffness<br />

Equivalent Stiffness<br />

Equivalent Stiffness<br />

Reduced Stiffness<br />

Reduced Stiffness<br />

Reduced Stiffness<br />

One steel grade only<br />

One steel grade only<br />

One steel grade only<br />

In Table 3, ""equivalent stiffness" refers to an equivalence criterion whereby the stiffness of the<br />

structure is kept constant; taking into account that higher strength concrete will have higher stiffness.<br />

"Reduced stiffness" refers to a criterion whereby a limiting elastic drift value governs the equivalence<br />

of two structures (this is selected as 0.02/R W as recommended in Uniform Building Code, 1994). "One<br />

steel grade" refers to structures where all slabs, beams and columns utilize the same steel grade. <strong>The</strong><br />

schedule of reinforcement and detailed drawings of the main lateral resisting elements, of the ten<br />

model structures, is given in Laogan and Elnashai (1999).<br />

RESULTS OF COST COMPARISON<br />

<strong>The</strong> assessment included not only the material costs, but also the cost of formwork. Considerable effort<br />

was expended in collecting realistic cost estimates from more than one source, but the significance of<br />

the study is more comparative than absolute. It was concluded that the most cost-effective structure is<br />

N80R. This is attributable to it using only a minimal amount of the expensive high yield steel (used in<br />

the beams only), while at the same time taking advantage of the large axial load carrying capacity of<br />

the high strength concrete to reduce the vertical steel reinforcement. Figure 2 shows a bar chart of the<br />

cost broken down into the different components.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!