最近读文章有些内容读不太懂,

最近读文章有些内容读不太懂,
Thus the performance target of a concrete linkslab can be summarized as:
• Adequate moment capacity to resist bending load caused by rotation of the adjacent slabs
due to expected maximum live loads
• Maintain durability by controlling crack widths in the slab in the presence of deck movement due to temperature variations,live load and material shrinkage
• Maintain hinge action to comply as much as possible with the original simple span design.
The first and second performance targets suggest high steel reinforcement ratios,while the
third target suggests a low ratio.These contradictory requirements can be resolved if the crack
width in the concrete can be self-controlled.This essentially decouples the need for crack
width control from steel reinforcement required for moment capacity assurance.Indeed,as the
link slab becomes more flexible with lower steel reinforcement ratios,the section stiffness and
therefore the moment induced actually decreases so that the first performance target can also be
met more easily.It is of course well known that normal concrete or even normal fiber reinforced
concrete does not have the capability of selfcontrolled crack widths.Once cracked,concrete
depends on steel reinforcement to control crack widths.

人工翻译,请审阅.
因此,一个混凝土链接桥板的性能目标可以概括为：1）有足够的抗弯承载力来抵抗相邻板块由于预期的最大活荷载引起的旋转导致的弯曲荷载；2）通过控制桥板在存在因温度变化、活荷载和材料收缩而引起的桥面移动时的裂纹宽度保持耐久性；3）保持铰链的作用尽可能符合原来的简单跨度设计.所述第一和第二个性能目标意味着高的钢筋增强比例,而第三目标建议采用低的比例.这些相互矛盾的要求可以得到解决,只要在混凝土中的裂缝宽度可得到自行控制.这实质上将裂缝宽度控制的需要与为保证抗弯承载力所需的钢丝增强分离了开来.的确,随着钢丝增强的比率下降,链接桥板变得更柔软（灵活）,桥段的刚性和因此感生的弯矩实际上下降了,从而第一种性能指标也可以更容易地满足.当然,众所周知,普通混凝土,或甚至通常的纤维增强混凝土不具备自我控制裂缝宽度的能力.一旦开裂,混凝土就取决于钢筋增强来控制裂缝宽度.