工字型钢不论是普通型还是轻型的，由于截面尺寸均相对较高、较窄，故对截面两个主袖的惯性矩相差较大，因此，一般仅能直接用于在其腹板平面内受弯的构件或将其组成格构式受力构件。
I-steel whether ordinary or light, because the section size are relatively high and narrow, so the moment of inertia of the main secti of the two sleeve is large, therefore, generally only can be directly used in the web plane bending member or the of lattice stress components.
H型钢的翼缘都是等厚度的，有轧制截面，也有由3块板焊接组成的组合截面。工字钢都是轧制截面，翼缘内边有1：10坡度。
Ｈ型钢的轧制不同于普通工字钢仅用一套水平轧辊，由于其翼缘较宽且无斜度(或斜度很小)，故须增设一组立式轧辊同时进行辊轧。
The flange of the H steel is equal thickness, has a rolling cross section, and a section of 3 plates. The I-steel is the rolling section, and the inner edge of the flange has the 1:10 gradient.
The rolling of H steel is different from ordinary I-beam only with a set of horizontal rolls. Because of its wide flange and no slope (or very ***all slope), a group of vertical rollers should be set up and rolled at the same time.
①胶合板有正反面的区别。挑选时，胶合板要木纹清晰，正面光洁平滑，不毛糙，要平整无滞手感。
②胶合板不应有破损、碰伤、硬伤、疤节等疵点。
1.the difference between the plywood and the and negative sides. When selecting, plywood should be clear, ***ooth, ***ooth, and ***ooth.
2. Plywood should not be damaged, bruised, hard or scarred.