As mentioned, You can add new stripLines dynamically by using the addTo method as shown in the code-snippet below,
chart.axisY[0].addTo("stripLines", {label: "2nd StripLine", value: 10})
Kindly, take a look at this JSFiddle for an example on adding 2 stripLines to a dynamic chart.
—
Adithya Menon
Team CanvasJS